Anti-Islanding Effect

The phenomenon where a photovoltaic power station continues to supply power to a section of the grid that has lost voltage after the grid fails is referred to as islanding. Islanding is categorized into unplanned islanding and planned islanding. The occurrence of unplanned islanding may endanger the lives of line maintenance personnel and users, disrupt the normal reclosing of the grid, and cause the frequency and voltage within the island to become uncontrolled.

According to the "Technical Regulations for the Integration of Photovoltaic Power Stations into the Grid" by the State Grid Corporation, unplanned islanding is prohibited in photovoltaic power stations. Photovoltaic power stations must possess the capability to rapidly detect islanding and immediately disconnect from the grid. Their anti-islanding protection must be coordinated with the line protection on the grid side.

Anti-islanding protection for photovoltaic power stations must include both active and passive methods, with at least one primary active and one primary passive anti-islanding protection mechanism implemented.

If a fault causes the public connection point to disconnect from the regional grid, and the output of the photovoltaic power station exactly matches the load at the public connection point, unplanned islanding occurs.

Within the island, parameters such as voltage, frequency, and phase change very little. Due to the limitations of protection mechanisms, inverters may struggle to detect the islanding phenomenon and disconnect promptly. However, since the output of photovoltaic power stations is unstable and the load is highly variable, the balance between output and load within the island will not be maintained for long. According to GB/T 19939-2005 "Technical Requirements for Grid-Connected Photovoltaic Systems," when the grid loses voltage, anti-islanding protection should act within 2 seconds to disconnect the photovoltaic system from the grid. The anti-islanding protection of the inverters planned for use in the photovoltaic power station can act within 2 seconds, disconnecting the photovoltaic system from the grid, thereby meeting the requirements of relevant national standards.

Mangzhong Construction is an integrated "design + product + service" supplier based on technological research and development, supported by design optimization, system integration, and intelligent operation and maintenance services. At the same time, Mangzhong Construction emphasizes investment in technological research and development, building a professional system design team to provide technical design services and optimization for photovoltaic power generation systems in different regions, of different types, and scales. Additionally, based on industry characteristics, customer needs, its own business strategies, and years of industry experience, the company offers digital, customized, and professional one-stop solutions for photovoltaic systems.

Company Name: Jiangsu Mangzhong Construction Co., Ltd.

Business Scope: Photovoltaic power station EPC and photovoltaic solar power station investment

Company Landline: 025-5888 3737   

Mobile Number: 159 5163 4545

Company Website: http://www.mangz.cn