Ye Xiaohui

A novel method for VSC-HVDC electromechanical transient modeling and simulation

VSC-HVDC (Voltage Source Converter High Voltage Direct Current) transmission system is a recent HVDC technology. The paper presents a new way of VSC-HVDC electromechanical transient modeling and simulation, which is based on the theory of equivalent sources. This method uses equivalent sources to substitute for voltage source converter, in addition, there are no simulation of IGBTs or PWM trigger modular, so it is more appropriate for electromechanical transient modeling and simulation. By this way, the detailed dynamic model for VSC-HVCD is developed. This model includes four parts, i.e. the normal ac system, the VSC-HVDC inner dc system, the interface between ac and dc system and the VSC-HVDC control system. Then a case of VSC-HVDC transmission system is established in PSCAD, the results show that by using this method for VSC-HVDC electromechanical transient modeling and simulation, not only the steady-state power flow can be controlled, but the system can achieve ideal dynamic response.

Power system risk assessment method based on dynamic power flow

Risk assessment theory is paid more and more attention to consider the random characteristics of power system, but traditional method could not consider the operating factors as frequency response of generators and loads, various emergency control measures. In this paper, a dynamic contingency analysis method base on dynamic load flow is proposed considering the above factors. The dynamic contingency analysis is a less time-consuming approach, but could simulate as well the detailed load shedding relay model, and the time-varying reliability model. So the proposed dynamic contingency analysis gives a good tool for cascading failure simulation.

Review on power system cascading failure thoeries and studies

A large number of blackouts have happened in power system recently, and most of them are cascading outages. Because of their severe consequences, a variety of methods are proposed to study the mechanism of cascading outages. These methods can be divided into four categories: self-organized critical theory, complex network theory, operational reliability theory, and power system simulation theory. This article reviewed the researches on cascading outages, and pointed out some important research achievements and their drawbacks.

Study of Credibility Evaluation of Dynamic Models and their Parameters

The time-domain simulation plays an important role in planning, designing and operation of the power system, but mismatches between its results and the actual system response show that the credibility evaluation of dynamic models is critical in all the above aspects of power systems. This paper discusses the technologies of credibility evaluation, including hybrid dynamic simulation with PMU measurements, error analysis and the calculated indices. Moreover, a phase shift method is presented to implement hybrid dynamic simulation in PSD-FDS. Then the paper proposes a credibility evaluation scheme to provide solution for the evaluation. At last, one sample is used to validate the implementation of hybrid dynamic simulation, while the other sample illustrates the effectiveness of the credibility evaluation approach.