Tong Xiaoyang

The analysis of communication architecture and control mode of wide area power systems control

Power systems get more unstable and insecure with more transmission congestion and smaller generation reserves. There is prospect of wide area control schemes meeting the challenge instead of traditional local ones. Communication network technologies, which have made a great stride during last decade, play an important role in the new schemes. Control systems based on wide area networks (WAN) are studied in this paper. Multi-agent concept is introduced to improve the control performance. A novel wide-area control system that utilizes phasor measurement unit (PMU), wide-area communication and multi-agent technology is presented. The distributed system architecture and multi-agent working mechanism are discussed in order to use phasor data and to realize optimal power system stability control.

A transformer online fault monitoring and diagnosis embedded system based on TCP/IP and Pub/Sub new technology

In the traditional transformer fault monitoring system, the LPU (Local Process Unit) usually sends the data to the MMC (Main Monitoring Computer), which completes the complicated fault diagnosis and is the process center. In this paper, a novel transformer monitoring system is presented. The LPUs, the embedded systems, are designed to possess of the approximately functions to MMC such as monitoring, diagnosing and alarm. The TCP/IP and the Pub/Sub (Publish/Subscribe) technology are used to realize the design of LPU. The TCP/IP protocol and the network chip make the LPU with high transmission speed. The complicated diagnosis task is dealt with by a computer with strong data treatment capacity. The LPU and MMC can subscribe some fault diagnosis subjects.

An adaptive distance backup protection setting scheme according to the power flow transfer

The removal of one of the transmission lines will cause power flow transfer. The transferred load of for the affected lines is different. According to the degree of the power flow transfer and using the flow transfer coefficient as the weight, this paper proposes an adaptive distance backup protection scheme. Based on the real-time flow distribution measured by the wide-area measurement system (WAMS), the flow transfer coefficient can be calculated. Then, using the coefficient as a weight, the degree of the setting impedance shrinkage can be adjusted. This scheme could not only prevent maloperation, but also identify the fault and it has the ability of enduring transition resistance. The simulation results on an IEEE 39-bus testing system illustrate the validity of the scheme.