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The fault characteristic of islanded microgrid is closely related to the control strategy of distributed generation (DG) and it is different from that of grid-connected microgrid. Also, the analysis of fault control strategy is an essential foundation of the fault location. This paper discussed the control strategy and output fault characteristic of V/f and PQ controlled DG. To establish the fault detection criterion of islanded microgrid, the coordinating control strategy between V/f and PQ controlled DG is presented. Based on the above fault analysis, the fault point is located by using a new fault detection method, which is based on the phase differences between the pre-fault bus voltage and the positive- sequence current fault component of the feeders. Finally, examples are simulated in PSCAD/EMTDC and the results verify the accuracy and effectiveness of the proposed fault detection method.
Ziwen Liang; Longhua Mu; Fan Zhang; Han Zhou; Xin Zhang. The fault detection method of islanded microgrid with the V/f controlled distributed generation. International Journal of Electrical Power & Energy Systems 2019, 112, 28 -35.
AMA StyleZiwen Liang, Longhua Mu, Fan Zhang, Han Zhou, Xin Zhang. The fault detection method of islanded microgrid with the V/f controlled distributed generation. International Journal of Electrical Power & Energy Systems. 2019; 112 ():28-35.
Chicago/Turabian StyleZiwen Liang; Longhua Mu; Fan Zhang; Han Zhou; Xin Zhang. 2019. "The fault detection method of islanded microgrid with the V/f controlled distributed generation." International Journal of Electrical Power & Energy Systems 112, no. : 28-35.
The black start capability is vital for microgrids, which can potentially improve the reliability of the power grid. This paper proposes a black start strategy for microgrids based on a parallel restoration strategy. Considering the characteristics of distributed generations (DGs), an evaluation model, which is used to assess the black start capability of DGs, is established by adopting the variation coefficient method. Thus, the DGs with good black start capability, which are selected by a diversity sequence method, are restored first in parallel under the constraints of DGs and network. During the selection process of recovery paths, line weight and node importance degree are proposed under the consideration of the node topological importance and the load importance as well as the backbone network restoration time. Therefore, the whole optimization of the reconstructed network is realized. Finally, the simulation results verify the feasibility and effectiveness of the strategy.
Jing Wang; Longhua Mu; Fan Zhang; Xin Zhang. A Parallel Restoration for Black Start of Microgrids Considering Characteristics of Distributed Generations. Energies 2017, 11, 1 .
AMA StyleJing Wang, Longhua Mu, Fan Zhang, Xin Zhang. A Parallel Restoration for Black Start of Microgrids Considering Characteristics of Distributed Generations. Energies. 2017; 11 (1):1.
Chicago/Turabian StyleJing Wang; Longhua Mu; Fan Zhang; Xin Zhang. 2017. "A Parallel Restoration for Black Start of Microgrids Considering Characteristics of Distributed Generations." Energies 11, no. 1: 1.
Multi-microgrid has many new characteristics, such as bi-directional power flows, flexible operation modes and variable fault currents with different control strategy of inverter interfaced distributed generations (IIDGs). All these featuring aspects pose challenges to multi-microgrid protection. In this paper, current and voltage characteristics of different feeders are analyzed when fault occurs in different positions of multi-microgrid. Based on the voltage and current distribution characteristics of the line parameters, a new protection scheme for the internal fault of multi-microgrid is proposed, which takes the change of phase difference and amplitude of measured bus admittance as the criterion. This scheme with high sensitivity and reliability, has a simple principle and is easy to be adjusted. PSCAD/EMTDC is used in simulation analysis, and simulation results have verified the correctness and effectiveness of the protection scheme.
Fan Zhang; Longhua Mu; Wenming Guo. New Protection Scheme for Internal Fault of Multi-Microgrid. 2017, 1 .
AMA StyleFan Zhang, Longhua Mu, Wenming Guo. New Protection Scheme for Internal Fault of Multi-Microgrid. . 2017; ():1.
Chicago/Turabian StyleFan Zhang; Longhua Mu; Wenming Guo. 2017. "New Protection Scheme for Internal Fault of Multi-Microgrid." , no. : 1.