Linfeng Gu

Nonlinear control of SSSC for power system stability enhancement

This paper presents a novel nonlinear adaptive control scheme of static synchronous series compensator (SSSC) to enhance the transient stability and damping for multi-machine power system. The SSSC device is treated as a first order voltage resource and the multi-machine system is simplified into a two-machine model. Based on the exact feedback linearization theory and adaptive control law, the nonlinear adaptive controller of SSSC is derived. Unknown system parameters are considered for improving robustness. The simulation results validate the efficacy of the proposed controller.

Analysis of load characteristic of typical user of urban distribution networks

With the rapidly increase of electric load in a cosmopolitan city Shanghai, the importance of the analysis of load characteristic of urban distribution networks has aroused peoples abroad attention. In order to find out the load level and characteristic, this article provides a specific theoretical analysis and applied research in project. Through searching the load database, we got the relevant load data of the typical user. Subsequently, the load index and the load characteristic were analyzed as well as the impact factors. The method has proved useful to learn the load characteristic of urban distribution networks in engineering application.

Experiments and operation characteristics of 3-phase 3-wire active power filter

The conventional passive filtering has been outdated since it detune with age, this may affect its filtering performance and also cause resonance problems, active power filters (APFs) are attractive solutions to solve harmonic-related power quality problems due to the development of power semiconductors, control theory and digital signal processors (DSP), and they have become the first choice for power quality solutions. This paper systematically investigates the 3-phase 3-wire active filter in 3-phase 3-wire and 3-phase 4-wire systems, and both the balanced and unbalanced situations are considered. It has been found by various experiments, that 3-phase 3-wire active filter works quite well in 3-phase system, however, the performance of 3-phase 3-wire active filter in 3-phase 4-wire system is unsatisfactory, and it may even inject unwanted harmonics to the grid under certain situations, which deteriorates power quality of distribution system.