摘要
以逆变器为主电源的交流电网对供电有很高的可靠性要求,当负载侧发生短路故障时,系统要求能够迅速切除故障支路,然后恢复对其他支路的正常供电,实现选择性保护。逆变电源组网具有短路电流不随短路点位置改变的特点,且逆变器处于限流运行时短路电流由逆变器控制。目前已有的逆变电源组网保护策略大多需要使用基于微处理器的数字继电器。针对380 V等级的逆变组网短路保护问题,提出了一种基于“阶梯限流”的短路保护策略,与断路器和熔断器等配电系统的常规保护元件进行配合就可以实现选择性保护,无须再使用较为复杂、昂贵的数字继电器,控制算法简单、易于实现。此外,给出了详细的保护整定过程和设计实例,可以用来指导系统的保护设计。实验结果表明,采用所提出的限流策略和保护整定方法,可以迅速把故障支路切除,实现选择性保护,避免扩大停电区域,验证了所提出策略的有效性。
The inverter-dominated ac grid requires high reliability. When short-circuit faults occur on the load side, it is required to remove the faulty branch quickly and restore power supply to other normal load branches to achieve selective protection. The inverter-dominated power grid has the characteristics that the short-circuit current does not change with the position of the short-circuit point and can be controlled by the inverter since the inverter is working in the current-limiting mode. Most of the existing inverter-based power grid selective protection strategies need to use microprocessor-based digital relays. Focusing on the short-circuit protection issue of 380 V-level inverter-based power grid, this paper proposes a protection strategy based on ‘echelon current limiting idea’, which can achieve selective protection by cooperating with the conventional protection components of power distribution system such as breakers and fuses. The control algorithm is simple and easy to implement, and there is no need to use microprocessor-based digital relays which are more complicated and expensive. In addition, the detailed protection setting process and design examples are given, which can be used to guide the protection design of the system. The experimental results show that the current limiting strategy and protection setting method proposed in this paper can quickly remove the fault branch, so as to achieve selective protection and avoid expanding the blackout area, and then the effectiveness of the proposed strategy has been verified.
作者
贺暕
刘邦银
段善旭
HE Jian;LIU Bangyin;DUAN Shanxu(State Key Laboratory of Advanced Electromagnetic Engineering and Technology,School of Electrical and Electronic Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2022年第6期2357-2365,共9页
High Voltage Engineering
基金
国家重点研发计划(2018YFB0106300)。
关键词
逆变电源组网
短路故障
阶梯限流
选择性保护
保护整定
inverter-based power grid
short-circuit fault
echelon current limiting
selective protection
protection setting
