Voltage sag problems in large‐scale clustering wind farms

Abstract

Accompanied by the development of large‐scale wind energy and integration into grid in China, wind farm cascading trip‐off accidents resulting from voltage sag have occurred frequently in the past few years. Before proposing countermeasures, it is necessary to clarify the voltage sag problem of wind farms. First, three voltage sag risk indices are proposed. Second, the simplified equivalent circuit of double fed induction generator (DFIG) for short‐circuit calculation, stochastic model of wind speed and the fault model of buses/lines are presented in this paper. Third, assessment method of voltage sag in wind farm, implemented by Digsilent dynamic programming language (DPL), is proposed to analyze the severity and probability of voltage sag. Finally, a case study of wind farm connected to WSCC nine‐bus benchmark systems is analyzed in detail, and the validity of the proposed approach is confirmed. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

A novel approach for voltage sag representation in a chemical industry: A case study

“…Therefore in Reference 18, a stochastic estimation of voltage sag is studied for a transmission system where solar photovoltaic is connected. Similarly, the probabilistic based fault rates are considered for the estimation of voltage sag when a 2 MW Doubly Fed Induction Generator is connected to a power system network 19 . The time‐varying fault rate along with the influence of generator scheduling is considered for yearly Predictable Sag Occurrences at sensitive load buses 20…”

“…Similarly, the probabilistic based fault rates are considered for the estimation of voltage sag when a 2 MW Doubly Fed Induction Generator is connected to a power system network. 19 The time-varying fault rate along with the influence of generator scheduling is considered for yearly Predictable Sag Occurrences at sensitive load buses. 20 A stochastic model is developed by considering the uniform fault rate and power system faults for the estimation of voltage sag annually.…”

Cascaded LC‐AC transformer unidirectional DC/DC converter with high stepping ratio

“…With the gradual exhaustion of conventional fossil fuels and the growing concerns for environmental conservation, the utilization of renewable energy has become a hot topic [1][2][3][4]. Associated with tax rebates and incentive bonuses provided by the government, it further promotes the prosperity of wind power and photovoltaic market worldwide [5,6]. As a consequence, numerous converter topologies dedicated toward the integration of distributed renewable generations have been proposed in the literature [7][8][9][10].…”