Maloth Naresh

Superconducting fault current limiter for grid connected power system protection

Now-a-days, superconducting fault current limiters are in general found increasing in land-based power systems due to the enhancement of the distribution system. To limit this current, up-gradation of expensive current limiting equipments is investigated by several researchers, and various fault current limiting techniques have been developed. Superconducting fault current limiter (SFCL) is used to reduce the effect of unforeseen disturbances within the grid in transmission and distribution system. In smart-grid trend, SFCL has proved itself to be most promising device. In this paper, SFCL is implemented in MATLAB/ SIMULINK environment for grid connected power system protection. A transient analysis is performed for 3-phase L-G faults at different locations of the grid. To validate the effectiveness of the device in the grid, transient analysis without SFCL, is performed. With this analysis optimal location for SFCL installation is identified. While analysis, multi-criteria formulation is considered and number of SFCL are installed within the grid for better protection. Amongst number of varieties of SFCL devices, used in power system, resistive type SFCL is discussed and analyzed in this paper. For simulation purpose, a wind farm with a capacity of 10 MVA is modeled. The methodology developed shows the optimal placement of the SFCL and results obtained ratify the application of SFCL.

Superconducting Fault Current Limiter for Grid Connected Power System Protection

Now-a-days, superconducting fault current limiters are in general found increasing in land-based power systems due to the enhancement of the distribution system. To limit this current, up-gradation of expensive current limiting equipments is investigated by several researchers, and various fault current limiting techniques have been developed. Superconducting fault current limiter (SFCL) is used to reduce the effect of unforeseen disturbances within the grid in transmission and distribution system. In smart-grid trend, SFCL has proved itself to be most promising device. In this paper, SFCL is implemented in MATLAB/ SIMULINK environment for grid connected power system protection. A transient analysis is performed for 3-phase L-G faults at different locations of the grid. To validate the effectiveness of the device in the grid, transient analysis without SFCL, is performed. With this analysis optimal location for SFCL installation is identified. While analysis, multi-criteria formulation is considered and number of SFCL are installed within the grid for better protection. Amongst number of varieties of SFCL devices, used in power system, resistive type SFCL is discussed and analyzed in this paper. For simulation purpose, a wind farm with a capacity of 10 MVA is modeled. The methodology developed shows the optimal placement of the SFCL and results obtained ratify the application of SFCL.

Modified multiplier SEPIC converter for high voltage DC applications

This paper presents a single-stage non-isolated modified multiplier SEPIC converter for high voltage gain. The modified and multiplier technique reported in the literature are used to conventional SEPIC converters to obtain high voltage gain and low voltage stress across the switch. The proposed topology combines merits of both of these techniques simultaneously in the SEPIC converter to evolve a new converter topology. It provides high voltage gain, simple circuit with single switch, lower input current ripple, reduced voltage across the switch, and allows high switching frequency. Even higher voltage gain can be obtained by adding additional multiplier levels. The paper describes the principle of operation of proposed converter, derivation of its static gain along with other parameters. MATLAB/ SIMLINK based simulation studies have been performed to justify the claimed features of the proposed converter.

Flux coupling type superconducting fault current limiter in a transmission and wind energy system

Now a days, Superconducting fault current limiter (SFCL) is emerged as one of the most accomplished fault current limiter (FCL) In this Paper, a flux coupling type SFCL is designed for limiting the fault current in isolated wind turbine generation system. The proposed Resistive and flux Coupling based super conducting fault current limiters have improved performance in terms of current limitation, higher reliability and lifetime and reduced material requirement. Superconducting fault current limiter (SFCL) appears as an excellent FCL which tends to satisfy above features. The whole research work and analysis has been carried out in MATLAB/SIMULINK environment for isolated wind energy system.

A passive islanding detection approach for distributed generation using rate of change of negative sequence voltage and current

In this paper a new passive islanding detection technique is proposed for distributed generation using rate of change of negative sequence voltage and current. The proposed technique is based on the voltage and current measurement at targeted distributed generation (DG). The retrieved voltage and current are converted into symmetrical component through sequence analyzer then rate of change of negative sequence voltage (ROCONSV) and rate of change of negative sequence current (ROCONSC) are calculated for islanding detection. ROCONSV and ROCONSC are tested for different active power mismatching and work effectively even power imbalance is less than 15%. The proposed technique detects islanding very fast less than one cycle. This technique is efficient and free from non detection zone (NDZ).

Power flow control and implementation of PFC rectifier for DC motor drive

This paper presents a new topology of harmonic injection current, connected for a grid mode and dc motor drive. The system power factor is low and it has high harmonic content in the current. The proposed Swiss rectifier is based on harmonic current injection methods on Power Flow Control and Implementation of PFC Rectifier for DC Motor Drive, dc-ac buck converter provides the bidirectional power flow the step up converter. The dc link capacitor to exchange the power with the three phase feeders, also it is conformed the harmonic current can be satisfied with the proposed method. The simulation Study is performed in MATLAB/ SIMULINK.

Power flow control and power quality issues in distributed generation system

This paper presents the power flow control and power quality improvement in DG system having dc-dc step up converter and dc-ac voltage source inverter interfaced to the grid. Inherently the system power factor is low and it has high harmonic content in the current. In this paper the harmonic mitigating pulse width modulation (PWM) technique have been used to reduce the harmonics for power quality improvement. The dc-ac converter provides the bidirectional power flow between point of common coupling (PCC) and local load. The step up converter regulates the dc link voltage to exchange the power with the three phase feeders. The simulation Study is performed in MATLAB/ SIMULINK.