并联逆变电源系统短路故障的选择性保护研究

In order to protect the switching devices from the damage, most of inverters disable the gate driver signals when a short-circuit fault occurs on the load side. Consequently, the output voltage lost can cause the failure or shutdown for the critical loads supplied by the inverters, making the power supply reliability drops greatly. Drawing on the experience of the classic relay protection in the power system, this project proposes a new idea of the selective protection for the parallel-connected inverter system. After the occurrence of the short-circuit fault, the system quickly detects, discriminates, and clears the fault. The critical loads can be continuously supplied by the parallel-connected inverter system. This method corrects the defect of the shutdown in the inverter system, therefore, the power supply reliability is enhanced. .Some research work will be conducted, including the structure layout of the parallel inverters, the output current control for different short-circuit impedance, the smooth transition at the different operational modes, the overcurrent interrupting protection and influence of the protection subsystem on parallel-connected inverter system. A parallel-connected inverter system prototype will be implemented, and the fast detection, effective control, and smooth transition strategies will be also analyzed for the parallel-connected inverter system. To clear the fault, the traditional circuit breaker with an inverse-time characteristic or new digital relay is used as the tripping components. Therefore, the design method of the upstream and downstream, and the setting principle of circuit breaker are simplified greatly in feeder line. As a result, the selective protection is realized.

现有逆变电源在遇到强过载、负载短路等故障时，为保证半导体开关器件不损坏，绝大部分实行停机保护，导致一些重要设备断电，系统的供电可靠性降低。借鉴传统电力系统继电保护的思路，针对并联逆变电源组成的电网，本项目提出采用选择性保护这一新思路，在遇到短路故障时，系统快速地检测、识别与切除短路的故障支路，保证重要负载的不间断供电，克服了以往逆变电源在遇到负载短路故障时停机保护的缺陷，从而提高系统供电的可靠性。拟从并联逆变电源的结构布置方式、不同短路阻抗条件下的故障电流输出特性、不同模式间的平滑切换、故障时的电流速断保护与保护子系统对并联逆变电源系统的影响几个方面开展研究，构建一个并联逆变电源研究平台，分析并联逆变电源的快速检测、有效控制和平滑切换方法，采用传统的机电式断路器或新型的数字继电器作为执行元件，简化馈电线路上下级的设计和断路器的整定，实现并联逆变电源系统的选择性保护。

在船舶、航空航天等独立供电系统领域，大量使用并联逆变电源作为主电源。逆变电源的核心是功率半导体开关器件，在遇到强过载、负载短路等故障时，为保证半导体开关器件不损坏，绝大部分实行停机保护，导致一些重要设备断电，系统的供电可靠性降低。. 本项目对独立供电系统故障后的连续高可靠供电问题开展了全面而深入的研究，提出了对并联逆变电源供电系统采用选择性保护的方法，创造性地研制出故障期大电流精确可控、故障恢复后快速电压重建的电压源型主供电电源，同时快速地检测、识别与切除短路的故障支路，保障关键负载的连续供电，有效避免了供电系统由局部故障发展为大面积失电，实现了系统的选择性保护，增强了系统供电可靠性。. 项目取得了集理论和技术于一体的系统创新性成果，创新成果有助于解决独立供电系统中电力电子装备的部分关键技术难题，提高舰船和飞机的战斗力和生命力，助推我国舰船和飞机电力电子装备的跨越式发展。

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