分布式发电系统保护方法研究

在分析分布式电源不同的短路特性的基础上,提出了利用自适应速断保护和故障分量保护作为分布式发电系统的保护方案,故障发生后,首先利用自适应速断保护,通过故障信息算出系统等效阻抗,同时判断出故障类型,代入自适应速断整定公式,设定速断动作阈值;其次,当自适应速断保护不满足动作要求时,利用故障前后电流,算出故障分量电流,以故障电流作为后备保护。本方案只需对传统保护进行软件升级,无需增添任何硬件成本,完全实现无通道线路保护,且当某个保护元件失灵时仍可保证跳开故障线路。通过对正常运行系统和孤岛进行仿真,结果证明了该方法的可靠性和可行性。

Distribution Generation System Protection Methods

The author proposed a novel method which made use of adaptive and fault component protection for distribution generation (DG) system based on the difference short circuit characteristics of DG. When the fault occured, adaptive current showes instantaneous trip protection ,which needs fault information to calculate the Thevenin equivalent impedance of system ,to estimate the fault type and to set threshold by adaptive current protection tuning formulate, is used for feeders protection. However, the adaptive protection do not always act when fault occurs. So backup protection is required which uses fault information to get the current fault component. This method which implemented with non-channel protection, only needs upgrade the software on the traditional protection without any hardware investment and achieves feeder protection under existing protection devices. Simulation results of normal and island operation verified the reliability and validity of this proposed method in DG system.