Special 72.5 kV ring main unit for offshore wind power

Abstract

A special 72.5 kV ring main unit for offshore wind power belongs to the technical field of power switches, and solves the problems that a 35kV ring main unit cannot be applied to a 72.5 kV system due to the limitation of voltage class, and the traditional high-voltage gas insulated switchgear and dry air insulated high-voltage gas insulated switchgear have large air leakage problems and are very inconvenient to maintain and repair. The ring main unit is characterized by comprising an upper gas tank serving as a circuit breaker gas tank and a lower gas tank serving as a submarine cable connecting gas tank, a first sealed operating mechanism is mounted outside the upper gas tank, and a second sealed operating mechanism and a third sealed operating mechanism are mounted outside the lower gas tank. The beneficial effects of the ring main unit are that one ring main unit simultaneously realizes the connection with a transformer at the generator side and the ring network connection with submarine cables at the two sides of a wind tower, the structure is compact, a sealed operation mechanism prevents the corrosion of salt mist and humid environment on the metal surface, and the requirements of offshore wind power on the transportation, installation and maintenance of electrical equipment are met.

Description

technical field [0001] The invention belongs to the technical field of power switches, in particular to a 72.5kV ring main unit specially used for offshore wind power. Background technique [0002] Offshore wind power, as a clean energy, has developed greatly in recent years, and its installed capacity has increased year by year, from 2 MW in the past to 8 MW and 12 MW. The ring main unit used in offshore wind power is installed in the wind power tower and is suitable for the high salt fog and high humidity operating environment in the ocean. In addition to meeting the system parameters and wiring requirements, due to the limitation of the tower body diameter, it is also required to be installed in the power tower The equipment inside is small in size, light in weight, easy to install and disassemble, and can be transported out from the oval tower door after the equipment is disassembled. [0003] There are three types of switchgear used in offshore wind power: [0004] Th...

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Problems solved by technology

[0005] The second type is the traditional high-voltage gas-insulated switchgear (GIS). After structural modification and offshore environment adaptability design, it is applied to the offshore wind power system. Although the voltage level can meet the requirements, because this GIS product uses SF 6 For gas insulated circuit breakers, the internal gas pressure of the equipment is relatively high (0.6-0.7MPa), and the gas leakage problem is relatively large

However, this utility model can only be used for the SF in the ring network cabinet 6 Whether the gas leaks is detected and diversion treatment is carried out to ensure the safety of the staff, but it cannot guarantee that there is no air leakage, so the normal operation of the wind turbine cannot be guaranteed

[0006] The third type is dry air-insulated high-voltage gas-insulated switchgear (GIS) using vacuum circuit breakers. This product uses dry air (79.5% N2+ 20.5% O2) with weak insulation capacity as the insulating medium, and has good environmental performance. It is superior to the second product, but even if a vacuum circuit breaker is used, the internal gas pressure of the equipment is still high (about 0.6MPa), the possibility of air leakage is still relatively large, and maintenance and repair are also very inconvenient. Once the air leaks, Will encounter the same problem as the second product, which will make the product lose its function and have a greater impact on the continuous operation of the generator

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