What Is A Four-Distributed Static Compensator

Modelling of the series transformer, VSC and LC filter is presented in this section. A time-varying threephase

It is observed that the power factor is maintained closer to unity when the input voltage is reduced from 230V to 110Vrms. Figure 11 (a) and (b) shows the power factor correction of controller for various load condition such as 20% (60W) and 75% (230W). The power factor for the system is found to be 0.84 for light load condition and 0.99 for full load condition. The THD of input current at full load with predominant third and fifth harmonic components are shown in Figure 12(a) and (b).Third harmonics is found to be 4.8% and fifth harmonic component is 4.9% which are well within IEC 61000-3-2 standard during wide range of load variations. The variation in power factor with load is shown graphically in Figure 13(a). It can be inferred from the graph that improved resettable control operates at high power factor for all load condition whereas the conventional PI control has poor power factor under light load conditions. Figure 13(b) shows the comparison between the efficiency of the converter for varying load conditions with the conventional control method and the resettable integrator control. The converter’s efficiency is maintained at 92% for light load conditions and 96% for fully loaded condition with integrator control technique. Thus the improved resettable integrator controller provides a very simple and reliable solution for power factor correction and

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The parameters of this controller (PI- 1) can be decreased during the voltage sag in order to improve the performance of the proposed method.

The DVR is one of the most common and effective solutions for protecting critical load against voltage sags [10] [11]. The DVR is a power electronic device used to inject three-phase voltages in series and in synchronism with the distribution feeder voltages in order to compensate for voltage sags. Moreover, it can be efficiently used to augment the fault ride through capability in wind applications. Detection time is an important factor in the voltage restitution process. Fast detection

Its implementation is very easy but its difficulty in calibration and maintains increases as the order of filter increases.one can easily design and modify a filter using digital signal processing (DSP).Filter function in digital signal processing (DSP) is software based, flexible and repeatable. In digital signal processing (DSP) filter with higher order only require software modification .whereas in analogue circuit we need additionally hardware implementation also. In short digital signal processing (DSP) is defined as the converting the continuously changing waveform (analog) into a series of discrete levels

Our proposed technique uses two windows in the same signal shifted from each other by one cycle time, this means the time interval hΔt = Ns Δt = 20 m Sec (for power system frequency = 50 Hz), where h = Ns = 50 samples (the number of samples per cycle used in the simulation), Δt is the sampling interval time = 0.4 m Sec. The number of samples per window (m) is an adjustable value for controlling the window size and the relay speed.

Adaptive filters have been successfully applied to diverse fields including communications, speech recognition, control systems, radar, seismology and biomedical engineering. Among various types of adaptive algorithms, the least-mean-square (LMS) algorithm is well known and widely adopted due to its simplicity and robustness to initial condition and noise. The performance of the LMS algorithm, in terms of convergence rate, maladjustment, mean-square error (MSE), and computational cost, is governed by the step- size. The frequency-domain (FD) adaptive filter algorithm is known to be able to reduce the numerical complexity by using the overlap-and-save implementation method. It incorporates block updating strategies where the fast Fourier

Figs. 8(a-c) show the generated stator, rotor and total active powers respectively. Total active power is identical to the estimated power curve in Fig. 2. Fig. 9 shows the stator reactive power while the rotor reactive power is taken from the DC bus system. The RSC has large size with the lead power factor (Qs= -1.6 MVAR), otherwise, all lag power factors have smaller RSC size.

Further, generator G1 is modeled as slack with 1.0 per unit voltage, while generator G2 is modeled as a PQ type with assigned active power of P = 40 MW and reactive power of Q = 30 MVAr.

Abstract—This paper describes the theory and simulation by mat lab of flexible Alternative Current Transmission Systems (FACTS) devices used in the disturbed power systems. One of these devices, Unified Power Flow Controller (UPFC)

2Control & Mechatronics Engineering, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81310 Skudai Johor Bahru, Malaysia

The increase of electronic equipments has caused the increase in the nonlinear loads and due to these loads power quality is being deteriorated. The supply voltage is distorted due to harmonic currents drawn from the supply by nonlinear loads. Distorted currents and voltage cause the user’s equipment to not work properly, conductors will overheat and may decrease the efficiency and life of the equipment. Usually a passive LC power filter is employed to wipe out the current harmonics

For emolument of current harmonics (if any), the instantaneous resoluteness of different active and reactive powers is utilized - the active and reactive powers are computed utilizing p-q theory. No restrictions are imposed on the voltage or current wave forms, and it can be applied to three-phase systems with or without a neutral wire for three-phase generic voltage and current wave forms. Thus, it is valid not only in steady state, but withal in transient states.

Semi-active control systems combine the best features of the passive and active ones. They have almost the same environmental robustness, mechanical simplicity and low cost as passive devices and can offer the adaptability of active control systems without requiring the associated large power sources.