Adaptability Study on Out-of-Step Separation Devices of Complex Multiinfeed AC/ DC Power Systems

The power flow distribution of the GuangxiGuangdong AC transmission section (GX-GD section) has changed greatly as Kunliulong and Lugaozhao three-terminal HVDC projects have been put into operation, and it is necessary to study on the adaptability of out-of-step separation devices. Based on the real primary system, an equivalent system model is proposed in this paper which can accurately locate the oscillation center and calculate the minimum voltage at the measuring point. Dynamic real-time simulation is carried out for various types and different principles of out-of-step separation devices. Typical problems such as unreliable out-of-step locking criterion in the fault process and device refusing to move when the oscillation center is located at the device installation point are found and solved At the same time, based on the power grid panoramic simulation test technology and the actual configuration of out-of-step separation devices, the problems in the coordination of out-of-step devices near the GX-GD section are comprehensively studied, and the suggestions of putting the wide area out-of-step separation system into operation as soon as possible are put forward. The improvement and optimization measures proposed in this paper have been applied in the real system.