scholarly journals Performances Analysis on Power Quality Problems Mitigation by using Unified Power Quality Conditioner (UPQC)

Author(s):  
May Phone Thit

Nowadays, power quality is one of the major problems in electric power distribution system. The poor power quality at distribution level can affect the operation and performance of sensitive and critical loads. In the distribution systems, poor power quality results in various problems such as higher power losses, harmonics, sag and swells in the voltage, and poor power factor., etc. Unified Power Quality Conditioner (UPQC) is the only versatile device which can mitigate several power quality problems related with distribution system. A UPQC that combines the operations of a Distribution Static Compensator (D-STATCOM) and Dynamic Voltage Restorer (DVR) together with the shunt and series active control devices. UPQC can solve the problems related to the voltage/current harmonics, voltage sag/swell and unbalance in distribution system. To evaluate the performance improvement in the system, a model of UPQC is developed in MATLAB/SIMULINK with a typical distribution network. In this research, UPQC is applied for power quality enhancement of Myaungtagar industrial distribution substation, Myanmar. Enhancements in power quality by UPQC are evaluated under maximum load condition.Keywords—Power Quality, UPQC, Series Controller, Shunt controller, Harmonics

Author(s):  
Khalaf Gaeid ◽  
Mounir T. Hamood

<p>With the increase of the complexion in the power distribution system, it is very possible that several kinds of power quality disturbances are happened in a power distribution system simultaneously.This paper proposes a unified power quality conditioner (UPQC) including a series and a shunt active power filter (APF) to compensate harmonics in both the distorted supply voltage and nonlinear load current. In the series APF control scheme, a proportional-integral (PI) controller , meanwhile a PI controller and are designed in the shunt APF control scheme to relieve harmonic currents produced by nonlinear loads. The DC voltage is maintained constant using Two degree of freedom proportional integral voltage controller(2DoFPI). The performance of the proposed UPQC is significantly improved compared to the conventional control strategy. The feasibility of the proposed UPQC control scheme is validated through the simulations.</p>


Author(s):  
A. Sathik Basha ◽  
M. Ramasamy

Increased utilization of nonlinear loads in the power distribution system with profound integration of renewable energy requires improved power quality control. This paper proposes a Reformed Second Order Generalized Integrated (R-SOGI) control scheme for enhancing the output of the Dynamic Voltage Restorer (DVR) for the objective of achieving the desired sinusoidal voltage wave shape at the common point of services and harmonic reduction. The DVR incorporates a Solar Photovoltaic (SPV) system using the Z-source Inverter (ZSI), providing the necessary active power to mitigate the voltage sag/swell and power demand. ZSI offers step-down as well as step-up abilities, it makes the converters to operate in the conditions of shoot-through. Therefore, the application of ZSI-based DVR topology seems very promising. The compensating reference voltage is generated by the R-SOGI algorithm, which offers superior output under conditions for grid voltage irregularities, including voltage sag/swell and unbalanced and distorted utility grid voltages. In comparison to DVR based on the VSI voltage inverter (VSI), the response from ZSI-DVR to a reduction of voltage distortions and harmonics is investigated. An experimental SPV ZSI-DVR prototype is developed in the laboratory to check the effectiveness of the controller and is tested under balanced and unbalanced supply and dynamic load conditions.


2016 ◽  
Vol 818 ◽  
pp. 52-57 ◽  
Author(s):  
Faridullah Kakar ◽  
Abdullah Asuhaimi bin Mohd Zin ◽  
Mohd Hafiz bin Habibuddin

Voltage sag and harmonics are the most frequent power quality problems faced by industrial and commercial customers today. Situation has been aggravated by modern sensitive industrial equipments which introduce system harmonics due to their inherent V-I characteristics. In this paper, proportional integral (PI) control technique based dynamic voltage restorer (DVR) is implemented in power distribution system to suppress voltage sag and harmonics under linear, non-linear and induction motor load conditions. Real-time power distribution system and DVR test models are built in Matlab/Simulink software. Simulation results exhibit excellent PI control approach with effective performance yielding excellent voltage regulation.


The Indian economy has been growing at a fast pace since the beginning of this millennium. Due to constraints in the availability of fuel and environmental concerns, the power generation sector has not kept pace with other industrial sectors. One way of increasing the power availability is by reducing the high losses in the existing power transmission and distribution systems. The current increases in the motor windings when the voltages in the three phases are unbalanced. Compensation for reactive power and unbalance in the power distribution system are key factors in improving the power quality to the end user. A Distributed Static Compensator [DSTATCOM] is a custom power device, which is connected in shunt with the load in the distribution system to compensate the reactive power due unbalanced loads. The performance of the DSTATCOM is based on the control technique used for finding the voltage referred and current components to be considered. Voltage compensation is defined as the error in voltage in the grid and that the value of voltage that has to be induced in the grid. This is analyzed by using DSTATCOM for voltage compensation with series converter controller block. This paper gives the simulation of voltage compensation to rectify the issue of voltage swell/sag in order to improve the power quality in the distribution system.


Author(s):  
Jasti Venkata Ramesh Babu ◽  
Malligunta Kiran Kumar

Power quality is one big issue in power system and a big challenge for power engineers today. Electrical consumers (or otherwise load devices) expect electrical power received power should be of first-class. Bad quality in electrical power directs to fuse blowing, machine overheating, increase in distribution losses, damage to sensitive load devices and many more. DSTATCOM is one of the FACTS controllers designed to improve the quality in electrical power and thus improving the performance of distribution system. This paper presents a multilevel DSTATCOM topology to enhance power quality in power distribution system delivering high-quality power to the customer load devices. Diode-clamped structure is employed for multi-level DSTATCOM structure. ‘PQ’ based control strategy generates reference signal which is further processed through level-shifted multi-carrier PWM strategy for the generation of gate pulses to multi-level DSTATCOM structure. Simulation work of proposed system is developed and the result analysis is presented using MATLAB/SIMULINK software. Performance of multi-level DSTATCOM topology is verified with fixed and variable loads.


2010 ◽  
Vol 61 (4) ◽  
pp. 193-204 ◽  
Author(s):  
Reza Noroozian ◽  
Mehrdad Abedi ◽  
Gevorg Gharehpetian

Combined Operation of AC and DC Distribution System with Distributed Generation Units This paper presents a DC distribution system which has been supplied by external AC systems as well as local DG units in order to demonstrate an overall solution to power quality issue. In this paper, the proposed operation method is demonstrated by simulation of power transfer between external AC systems, DG units, AC and DC loads. The power flow control in DC distribution system has been achieved by network converters and DG converters. Also, the mathematical model of the network, DG and load converters are obtained by using the average technique, which allows converter systems accurately simulated and control strategies for this converters is achieved. A suitable control strategy for network converters has been proposed that involves DC voltage droop regulator and novel instantaneous power regulation scheme. Also, a novel control technique has been proposed for DG converters. In this paper, a novel control system based on stationary and synchronously rotating reference frame has been proposed for load converters for supplying AC loads connected to the DC bus by balanced voltages. The several case studies have been studied based on proposed methods. The simulation results show that DC distribution systems including DG units can improve the power quality at the point of common coupling (PCC) in the power distribution system or industrial power system.


Author(s):  
Dung Vo Tien ◽  
Radomir Gono ◽  
Zbigniew Leonowicz

Power quality is a major concern in electrical power systems. The power quality disturbances such as sags, swells, harmonic distortion and other interruptions have impact on the electrical devices and machines and in severe cases can cause serious damages. Therefore it is required to recognize and compensate all types of disturbances at an earliest to ensure normal and efficient operation of the power system. To solve these problems, many types of power devices are used. At the present time, one of those devices, Dynamic Voltage Restorer (DVR) is the most efficient and effective device used in power distribution system. In this paper, design and modeling of a new structure of multifunctional DVR for voltage correction is presented. The performance of the device under different conditions such as voltage swell, voltage sag due to symmetrical and unsymmetrical short circuit, starting of motors, and voltage distortion are described. Simulation result shows the superior capability of proposed DVR to improve power quality under different operating conditions. The proposed new DVR controller is able to detect the voltage disturbances and control the converter to inject appropriate voltages independently for each phase and compensate to load voltage through three single- phase transformers.


2021 ◽  
Vol 309 ◽  
pp. 01108
Author(s):  
Someshwara Thota ◽  
Vinay Kumar Awaar ◽  
Praveen Jugge ◽  
S Tara Kalyani

Voltage sag and voltage swell are frequently occurred power quality problems in present power distribution system, which are cause more problems to avoid these problems and maintain constant voltage at sensitive load during sag and swell Dynamic voltage restorer gives solution .we propose self-supported DVR, to minimize the cost by preventing external dc source in DVR, it is controlled by SRF PI control along with an inner current loop to stabilize the system and outer voltage loop to increase the system robustness. The proposed model provides fast voltage restoration for a short and long duration of voltage sags and swells manage wide load current variation for short and long voltage disturbances. In this paper, we present the effectiveness of the proposed method by using MATLAB/simulation results. A laboratory prototype DVR is modelled and we are using CCS studio to interface DSPTMS320F28027F


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