scholarly journals Harmonic Mitigation Using Passive Harmonic Filters: Case Study in a Steel Mill Power System

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2278
Author(s):  
Byungju Park ◽  
Jaehyeong Lee ◽  
Hangkyu Yoo ◽  
Gilsoo Jang

In this study, we mitigated the harmonic voltage in a power system that contained the roughing mill (RM) and finishing mill (FM) motor drives. AC/DC converter type RM drive is a non-linear, large-capacity varying load that adversely affects power quality, e.g., a flicker, voltage distortion, etc. The voltage drop can be compensated within a certain limit by using the proper capacity of a power capacitor bank. In addition, the voltage distortion can be controlled as per the guidelines of IEEE Std. 519 using the passive harmonic filter corresponding to the characteristic harmonics of the motor drive load. The passive harmonic filter can provide an economical solution by mitigating the harmonic distortion with a proper reactive power supply. However, at the planning level, attention should be paid to avoid system overvoltage that is caused by the leading power under light load conditions and also the problem of parallel resonance between the harmonic filter and the step-down transformer. In addition, when designing the filter reactor, the K-factor and peak voltage must be considered; the filter capacitor also requires a dielectric material that considers the harmonic peak voltage. The purpose of this study was to acquire a better understanding of the filter applications as well as verify the field measurement, analysis, and design of harmonic filters together with its performance.

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 585
Author(s):  
Atoosa Majlesi ◽  
Mohammad Reza Miveh ◽  
Ali Asghar Ghadimi ◽  
Akhtar Kalam

In recent years, grid-connected photovoltaic (PV) power generations have become the most extensively used energy resource among other types of renewable energies. Increasing integration of PV sources into the power network and their dynamic performances under fault conditions is an important issue for grid code requirements. In this paper, a PV source as a unified interphase power controller (UIPC) is used to enhance the low voltage ride through (LVRT) and transient stability of a multi-machine power system. The suggested PV-based UIPC consists of two series voltage inverters and a parallel inverter. The UIPC injects the required active and reactive power to prevent voltage drop under grid fault conditions. Accordingly, a dynamic control system is designed based on proportional-integral (PI) controllers for the PV-based UIPC to operate in both normal and fault conditions. Simulations are done using Matlab/Simulink software, and the performance of the PV-based UIPC is compared with the conventional unified power flow controller (UPFC). The results of this study indicate the more favorable impact of the PV-based UIPC on the system compared to UPFC in improving LVRT capabilities and transient stability.


2016 ◽  
Vol 19 (1) ◽  
pp. 5-19
Author(s):  
Phuong Minh Le ◽  
Huy Minh Nguyen ◽  
Hoa Thi Xuan Pham ◽  
Tho Quang Tran

This paper presents a new load sharing technique for parallel-connected three-phase inverters in Standelone Microgrid. The paper proposed improvements droop controller to accurate load share by ratio with rated power of the inverter. In addition, the proposed scheme ensures reduced load voltage droop due to the load and droop. In the paper, the active power and reactive power are divided by voltage regulation under reference voltage in conditions of stark difference between line impedances, In addition the paper presents the ability to overcome the disadvantages of traditional droop scheme. The proposed model is simulated by Matlab-Simulink for 3 parallel-connected threephase inverters. The simulation results proved the technical soundness and advantages of the proposed in comparision with a tradition scheme even if the output impedance is resistance reactance in power sharing and load voltage drop reduce problems.


In recent years, voltage stability problems have been increasing since power systems operate close to stability limits. The voltage stability problem of a power system is associated with a rapid voltage drop due to heavy system load and it occurs because of inadequate reactive power support at some critical bus. One of the serious consequences of the voltage stability is a system blackout, and this has received more attention in recent years. Accurate determination of stability limit and amount of reactive power injection to stabilize is important.This paper proposes to determine voltage stability margin of a critical bus and also provide amount of reactive power injection to the bus particularly during overload, a simple two bus equivalent model of the power system is used to determine the maximum apparent power for different power factors. Any required apparent power can directly obtained by correcting the reactive power at critical bus. Experimental results support our theoretical findings.


2011 ◽  
Vol 383-390 ◽  
pp. 2346-2349
Author(s):  
Jie Luo ◽  
Wen Hui Wu

Power flow analysis plays a significant role in both design and operational stage. The purpose of any load flow analysis is to compute accurate steady state voltages and voltage angles of all buses in a network, the real and reactive power flows into every line and transformer, under the assumption of known generation and load. This paper focus on fast decoupled flow, a practical power system has been used as an example to introduce its application in actual calculation, what’s more, develops a fast decoupled load flow calculation program for n-node system by taking advantage of MATLAB. A visual GUI interface is also established with MATLAB. In addition, the paper proposes a new simple power system data format, different from the IEEE standard one. The correctness and simplicity of the proposed format is verified through IEEE-5bus,-9bus,-11bus,-39bus systems.


2015 ◽  
Vol 63 (1) ◽  
pp. 261-267 ◽  
Author(s):  
L. Liu ◽  
C. Liu

Abstract An efficient phase locked loop (PLL) method is very important to improve the grid-connected efficiency and the locked speed of frequency, phase, and voltage. However, most of literatures only introduce one PLL or one modified PLL method. There are many grid faults due to the grid connection to the renewable power generating system. A comparison and analysis is very important to select the most effective PLL technology for the grid-connected control of the renewable power system. Three PLL technologies are compared at different grid faults, such as single phase voltage drop, two phase voltage drop, frequency deviation, and voltage distortion. Simulation results indicated that different PLL methods have different locked performances at different grid faults.


Author(s):  
Mohammed Salheen Alatshan ◽  
Ibrahim Alhamrouni ◽  
Tole Sutikno ◽  
Awang Jusoh

The electronic equipments are extremely sensitive to variation in electric supply. The increasing of a nonlinear system with several interconnected unpredicted and non-linear loads are causing some problems to the power system. The major problem facing the power system is power quality, controlling of reactive power and voltage drop. A static synchronous compensator (STATCOM) is an important device commonly used for compensation purposes, it can provide reactive support to a bus to compensate voltage level. In this paper, the Artificial Neural Network (ANN) controlled STATCOM has been designed to replace the conventional PI controller to enhance the STATCOM performance. The ANN controller is proposed due to its simple structure, adaptability, robustness, considering the power grid non linearities. The ANN is trained offline using data from the PI controller. The performance of STATCOM with case of Load increasing and three-phase faults case was analyzed using MATLAB/Simulink software on the IEEE 14-bus system. The comprehensive result of the PI and ANN controllers has demonstrated the effectiveness of the proposed ANN controller in enhancing the STATCOM performance for Voltage profile at different operating conditions. Furthermore, it has produced better results than the conventional PI controller.


Author(s):  
Robi Kurniawan ◽  
Ardiansyah Nasution ◽  
Arnawan Hasibuan ◽  
Muzamir Isa ◽  
Muskan Gard ◽  
...  

Distributed Generation (DG) is a small capacity generator located in the electricity distribution system and is usually placed on buses that are connected directly to the load. Placement of distributed generation is one of the technical efforts to reduce voltage drop and power losses in the system. In addition, load flow analysis is a study to plan and determine the amount of power in an electric power system. The results of power losses after adding distributed generation were the best in the fifth experiment on bus 149, where the system experienced a total loss of active power (P) previously of 720,822 kW, to 682,939 kW and total loss of reactive power (Q) previously of 530.02 kVar, to 405.835 kVar. From the results of the calculation of the power flow using ETAP software (Electrical Transient Analyzer Program). So, it can be concluded that the electrical network system can be said to be good. The results obtained are the more DG (wind turbine generator) that is input into the bus it will reduce the voltage drop that occurs. After simulating the overall voltage drop, it still meets the standards according to the results of the Text Report on ETAP.


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