To meet the augmented load power demand, the doubly-fed induction generator (DFIG) based wind electrical power conversion system (WECS) is a better alternative. Further, to enhance the power flow capability and raise security margin in the power system, the STATCOM type FACTS devices can be adopted as an external reactive power source. In this paper, a three-level STATCOM coordinates the system with its dc terminal voltage is connected to the common back-to-back converters. Hence, a lookup table-based control scheme in the outer control loops is adopted in the Rotor Side Converter (RSC) and the grid side converter (GSC) of DFIG to improve power flow transfer and better dynamic as well as transient stability. Moreover, the DC capacitor bank of the STATCOM and DFIG converters connected to a common dc point. The main objectives of the work are to improve voltage mitigation, operation of DFIG during symmetrical and asymmetrical faults, and limit surge currents. The DFIG parameters like winding currents, torque, rotor speed are examined at 50%, 80% and 100% comparing with earlier works. Further, we studied the DFIG system performance at 30%, 60%, and 80% symmetrical voltage dip. Zero-voltage fault ride through is investigated with proposed technique under symmetrical and asymmetrical LG fault for super-synchronous (1.2 p.u.) speed and sub-synchronous (0.8 p.u.) rotor speed. Finally, the DFIG system performance is studied with different phases to ground faults with and without a three-level STATCOM.

There are many objectives in a power system for better operation of generator units which needs to be satisfied both in terms of economic and technical constraints. The objectives like operating and running cost, reliability, emissions, multi-area unit commitment, losses, voltage stability, reactive power etc., are mostly considered in a large power system network with multiple generating units. In order to solve such large units in less operating time with accuracy, meta-heuristic methods are found to be feasible. Hence, this paper discusses different linear and non-linear and meta-heuristic methods applicable to power systems available in the literature. The review is done based on the method adopted, applicability and the technique adopted. A comparison is done among most of the optimization techniques in terms of accuracy, quicker in getting convergence, reliability, and its applicability in terms of single or multi-objective.

Short-term load forecasting (STLF) is an integral component of energy management systems. In this paper, fuzzy logic-based algorithm is used for short-term load forecasting. The load changes over time and the goal is to satisfy the shift in demand and to maintain a fault as low as possible between the reference and real powers. The error in the load demand in mega-watt (MW) is compared with proposed technique as well as conventional methods. Three cases were investigated in which the load changes were 1) more random in nature, but the variance to the reference was more; 2) the random load changes were simpler, but a little different from the reference; and lastly, 3) the load changing was random, and the reference deviation was maximum. The results are analyzed for different load changes, and the corresponding results are verified using MATLAB. The deviation of the error value in load response is less experienced with a fuzzy logic controller than with a traditional system, and in fewer iterations, the objective function is also achieved.

Doubly Fed Induction Generator (DFIG) needs to get adopted to change in wind speeds with sudden change in reactive power or grid terminal voltage as it is required for maintaining synchronism and stability as per modern grid rules. This paper proposes a controller for DFIG converters and optimal tip speed ratio based maximum power point tracking (MPPT) for turbine to maintain equilibrium in rotor speed, generator torque, and stator and rotor voltages and also to meet desired reference real power during the turbulences like sudden change in reactive power or voltage with concurrently changing wind speed. The performance of DFIG is compared when there is change in wind speed only, changes in reactive power and variation in grid voltage along with variation in wind speed.

The increase in the wind speed or rotor speed will decrease the doubly-fed induction generators (DFIG) terminal voltage which will increase the undesired reactive power flow from it. Hence, in this paper extraction of optimal power and control of reactive power is analyzed. For this, independent control of real and reactive power is done using the proposed reference power-based improved field-oriented control scheme. The rotor side controller is designed to run the rotor at specified optimal speed and also control of reactive power from the rotor side based on the grid requirement. In this work, only a wind speed sensor is required, and there is no need for rotor speed sensor, real power sensor, and torque sensor and hence, is cost-effective and lesser parameter dependency. Rotor speed and torque are predicted using measured stator voltage and stator and rotor current and also using the derived rotor flux. The performance of the DFIG system is examined in a simulation environment for rapid changes in rotor speed, wind speed, grid reactive power. There is smoother rotor speed changing, and rapid reactive power support from the DFIG.