Research On Online Transient Stability Prediction And Real-time Communication Of Stability Control

With the formation of interconnected power system and electricity markets, the requirement of power system for stability control system becomes much higher. Online transient stability prediction and real-time communication method ensure the real-time performance and reliability of stability control. Fast and accurately predicating system stability can save the time of online transient stability analysis; real-time communication is very helpful to realize the real-time transmission of the information and control commands. In the paper, methods for online transient stability prediction are researched. After analyzing the shortage and advantage of these methods, a new transient stability prediction method is presented based on two-cluster instability mode, which considers the relative motion in one cluster and the factor of damping. On the assumption that the rotator angle swing of any two generators in the same cluster is linear, the system model is simplified. It takes short-period time-domain simulative data as inputs and system identification theory is applied in computing model parameters. The damping coefficient and inertia time constant of generator may be unknown beforehand. Simulation on New England 39 Buses System illustrates that the method can improve the veracity of stability prediction efficiently. In the paper, the communication schemes used before are analyzed. Considering the condition of power system communication network, a communication scheme based on G.703 protocol is presented for meeting the need of stability control. The communicate system is mainly made up with a serial communication interface board and a 64k/2M multiplex interface device. The communication interface board is used in serial communication based on HDLC protocol, so a serial communication controller made by Siemens is used. The communication speed can reach as high as 4Mbps. 64k/2M multiplex interface device is used for producing code matched with G.703 protocol, so stability control system can be connected to power communication network. Because the distance between the board and the multiplex interface device may be several hundred meters, the optical fiber is used to enhance anti-interference capability. Experimentation illustrates that the communication system can work at speed of 2Mbps stably.