This paper proposes UPQC to enhance all Power Quality issues. The UPQC is outlined by consolidating a series APF and shunt APF. The adaptable FLC together with Series APF controls the voltage distortion. Shunt APFs operation is controlled by d-q axes current from load current and DC-interface voltage is maintained through adaptable FLC. The stationary and transient action of the controller circuit in various load current and variable voltage conditions is discussed. A versatile FLC is planned for the plant when its parameters are changing. The UPQC is used with static and switching nonlinear burdens. It can reduce voltage sag/swell, voltage variations and eliminates harmonics and so on. The proposed controller is implemented using MATLAB or Simulink.

In this paper, the mathematical Analysis of UPQC which is combination of Shunt-APF and Series-APF in distribution power systems discussed. It is more extensive by adding a series VSC from feeder to feeder. UPQC is added in each line coming from various substations to mitigate different power quality problems to maintain good voltage profile at supply side and the load end current disturbances in distribution power systems. The d-q method and p-q concept are used for controlling of UPQC. Mathematical analysis of UPQC in detail is discussed. In this paper, the UPQC based mathematical approach to mitigate all power quality issues has been developed by using MATLAB/Simulink.

The nonlinear characteristics of power electronic-based loads in a power system contribute a major role in the harmonics’ injection and other power quality disturbances. This affects the quality of the power supplied to consumers by distribution systems. Flexible AC transmission system (FACTS) devices at the transmission level and custom power devices at the distribution level are used for an effective power transfer. In addition to these devices, filters play a prominent role in distribution systems. This paper aims to analyze the supply voltage in the time–frequency domain to perceive the variations in signal strength, explaining the role and significance of filters in mitigating or reducing harmonics. This paper presents the significance of harmonic filters in terms of signal-processing terminology. This depicts the prominent role of filters in improving the power quality by harmonic reduction or elimination, depending upon the requirement. The mathematical transform used in this approach is the short-time Fourier transform, which results in transforming the signal into a domain giving information about time and frequency. A MATLAB Simulink environment and ‘spectrogram’ were used to simulate harmonic signals, and we analyzed them using a short-time Fourier transform. Different windows were used with varying window size lengths.

Micro grid is proposed in this paper to improve power quality in power distribution networks. The problem of power quality is addressed by (UPQC), cooperative control system for voltage harmonics,unbalances in micro grid(MG). Power control techniques employing one-stage converter for grid interaction MG system are presented in order to reduce many DC-AC-DC conversions in both AC,DC grids.The MG with suggested converter are used with variety of renewable energy sources, allowing for optimal power consumption in environ-mentally friendly settings with minimal losses, hence increasing system efficiency. The fuzzy type-II controller for frequency tracking,harmonic extraction in grid voltage,load currents is also proposed in this study. MATLAB/Simulink is used to verify this system, and the findings are adequate.