直流系统是支撑高比例新能源接入与灵活高效用能的重要技术方向.固态式直流断路器(solid state DC circuit breaker,SSCB)具有开断速度极快、无电弧、寿命长等优点,在中低压直流系统的故障保护中得到广泛应用.随着电力电子器件的发展,固态式直流断路器的拓扑结构、工作性能也在不断进步.为此基于逆阻型集成门极换流晶闸管(intergated gate commutate thyristor,IGCT),提出了一种新型的固态式直流断路器结构及设计方法,通流支路采用逆阻IGCT反并联结构实现双向通流,缓冲支路采用金属氧化物避雷器(metal oxide varistor,MOV)-电容结构来抑制过电压,吸能支路采用MOV吸收系统能量.进一步地,给出了关键元器件的参数设计方法,并验证了有效性;设计了性能良好的重力热管散热器,单个模块散热功率可达700 W;提出了主被动结合的控保策略,提高断路器的保护性能.最后,研制了固态式直流断路器样机,可用于750 V以内的低压直流系统,额定通流可达2 kA,可在百微秒内开断10 kA故障电流,成本低、体积小、高可靠,具有良好的应用前景.
Abstract
DC systems are an important technical direction that supports a high proportion of new energy access and flexible and efficient energy use.Solid state DC circuit breaker has the advantages of extremely fast breaking speed,sim-ple structure,and service life,and is widely used in medium and low voltage DC systems.With the development of power electronic devices,the topology and working performance of solid-state DC circuit breakers are also constantly improving.Based on the reverse blocking intergrated gate commutated thyristor(IGCT),this paper proposes a new type of solid-state DC circuit breaker structure:the main branch adopts the reverse blocking IGCT anti-parallel structure to realize bidirec-tional flow.The snubber branch adopts the MOV-C structure to suppress overvoltage and AC harmonics wave.At the same time,the parameter design method of key components is given and verified,a gravity heat pipe radiator with 700 W heat dissipation power is designed,and a control strategy is proposed to improve the reliability of the circuit breaker.Fi-nally,a 750 V/2 kA solid-state DC circuit breaker prototype is developed and passes the long-term test and breaking test with 10 kA maximum turn-off current.It has the advantages of low cost,small size,high reliability and good application prospects.
关键词
直流输配电/固态式直流断路器/逆阻型IGCT/反并联结构/缓冲设计
Key words
DC transmission and distribution/solid-state DC circuit breaker/reverse blocking IGCT/anti-parallel struc-ture/snubber branch design
维普
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