Cooling system used for ultrahigh voltage DC power transmission converter valve

Abstract

The invention provides a cooling system used for an ultrahigh voltage DC power transmission converter valve. The ultrahigh voltage DC power transmission converter valve comprises a converter valve 18formed by series connection of thyristor converter valve modules 13. A DC power transmission cooling system comprises a primary cooling system and a secondary cooling system. The primary cooling system comprises a condenser 8 and the equipped heat exchange component thereof. The secondary cooling system comprises a secondary cooling medium return pipe 14, a secondary cooling device 15, a circulating pump 16 and a secondary cooling medium outlet pipe 17. The cooling system is convenient to maintain and great in economic performance. The phase change cooling medium circulating power in the phasechange cooling system is provided by the thermal loss of the thyristor and the damping resistor and other components without external power so that the whole system is enabled to self-form the independent self-circulating system.

Description

technical field [0001] The invention relates to the field of ultra-high voltage direct current transmission converter valves, in particular to a cooling system for ultra-high voltage direct current transmission converter valves. Background technique [0002] With the development of HVDC transmission technology, the cooling method of UHVDC converter valves has undergone air cooling and oil cooling to the current water cooling method. Compared with air cooling and oil cooling, water has the highest thermal conductivity and the largest specific heat capacity. The convective heat transfer capacity is the strongest, and the convective heat transfer coefficient ratio of air, oil, and water is 1:10:100, so the cooling effect can be greatly improved by using water cooling. Under the same cooling conditions, the rated current of the thyristor using water cooling circulation can be greatly improved. . However, in recent years, with the rapid development of my country's UHVDC transmis...

AI Technical Summary

Problems solved by technology

However, in recent years, with the rapid development of my country's UHVDC transmission, the current has been increased from 5000A to 6250A, and the voltage level has been increased from ±800kV to ±1100kV, resulting in a significant increase in the loss of the converter valve of the UHVDC core equipment and the power of components. The corresponding increase in density brings great challenges to the cooling of power electronic components such as thyristors, saturable reactors and damping resistors

[0003] At present, the water-cooling method has a series of problems such as low cooling efficiency, complex water treatment system, uneven temperature distribution, galvanic corrosion scaling, and insulation failure caused by leakage, which cannot better meet the needs of large-capacity DC transmission projects. The UHVDC converter valve and its cooling system for operating under climatic conditions creatively combine the phase change cooling system (primary cooling system) and the secondary cooling system. The primary cooling system uses the phase change of the cooling medium for heat exchange. Under the unit temperature difference, the theoretical phase change heat transfer is 25 times that of water cooling. It has the characteristics of higher heat transfer efficiency, smaller volume, and can form a cooling circuit without external power. Then, the secondary cooling system passes the secondary cooling water and Condenser indirect heat transfer to remove heat

[0004] Existing research on phase change cooling technology focuses on technical fields such as generators, power tubes, and GTO inverters. The relevant research on the combined use of secondary cooling systems. The selection of phase change cooling medium is the key to phase change cooling technology. It is necessary to study the heat flow characteristics, electrical insulation, material corrosion and environmental friendliness of phase change cooling medium in depth.

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