scholarly journals Signatures of Transient Overvoltages in Low Voltage Power Systems in Tea Factories and Their Implications on Insulation Deterioration and Allied Power Quality Issues

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Earl A. R. L. Pannila ◽  
Mahesh Edirisinghe

Electrical equipment and supply cables demand a better quality of supply, with the recent advancements in integrated sensitive solid-state controls. Divergently, proliferated heavy inductive motors and some performance additions based on power electronics have introduced power quality issues to the network. Thus, this study mainly investigates the impact of switching transients generated by electromechanical machines in industrial power systems on insulation deterioration while taking transient overvoltages due to capacitor bank switching also to support. Transients with a high rate of rise are likely to catalyze the degradation of the insulation quality and break down the insulating material through ionization. These steeply passing overvoltage stresses let partial discharges ensue, which can attack the insulation over long service. To unveil this danger, 314 common-mode transient waveforms were measured in the electrical machines of five tea factories in Sri Lanka, in a 50 ms measurement window, taken in 55 measuring attempts. Most of the transients observed are in the form of a damped oscillatory waveform tailed by fast exponential collapse. That correlates to insulation degradation having a very steep rise as 30.04 V/ns, the highest at the withering section. When machines are heavily loaded, situations tend to generate transients with high amplitudes. There were transient bursts that spread as 426.3 ms, while 14 ns fast rise times were recorded from withering motors. Unlike electrical resonance and power-frequency overvoltages, electromagnetic switching transients last even less than 100 ms. To underline this, an analysis of the frequency domain of transients was also presented, which proves high density of high-frequency components reaching 107 kHz range. Accepting the fact that frequency and amplitude are always under the influences of innumerable dynamics, the observational evidence of the study endorses that electrical stress built by the transient nature of the factories reduces the life expectancy of electrical insulation.

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1688 ◽  
Author(s):  
C. Birk Jones ◽  
Matthew Lave ◽  
William Vining ◽  
Brooke Marshall Garcia

An increase in Electric Vehicles (EV) will result in higher demands on the distribution electric power systems (EPS) which may result in thermal line overloading and low voltage violations. To understand the impact, this work simulates two EV charging scenarios (home- and work-dominant) under potential 2030 EV adoption levels on 10 actual distribution feeders that support residential, commercial, and industrial loads. The simulations include actual driving patterns of existing (non-EV) vehicles taken from global positioning system (GPS) data. The GPS driving behaviors, which explain the spatial and temporal EV charging demands, provide information on each vehicles travel distance, dwell locations, and dwell durations. Then, the EPS simulations incorporate the EV charging demands to calculate the power flow across the feeder. Simulation results show that voltage impacts are modest (less than 0.01 p.u.), likely due to robust feeder designs and the models only represent the high-voltage (“primary”) system components. Line loading impacts are more noticeable, with a maximum increase of about 15%. Additionally, the feeder peak load times experience a slight shift for residential and mixed feeders (≈1 h), not at all for the industrial, and 8 h for the commercial feeder.


Author(s):  
C.S Boopathi ◽  
Kuppusamy Selvakumar ◽  
Avisek Dutta

In this paper unified power quality conditioner has been used to enhance low voltage ride through capability of grid connected wind conversion system taking Doubly fed induction generator (DFIG). Unified Power quality conditioner (UPQC) device is a combination of series active filter and shunt active filter. This custom power device is mainly used to mitigate power quality issues which is an essential factor today because of wide application of power electronics devices. UPQC is capable to deal with voltage and current imperfection simultaneously. It is installed in the system mainly to improve the power quality i.e. Voltage sag/swell, Harmonics, reactive power compensation etc. at point of common coupling. System is modeled in MATLAB/SIMULINK and results shows utilization of UPQC for the enhancement of LVRT of a DFIG wind system according to Grid code. when fault occurs in the system, it will create voltage dip and series compensator of UPQC injects during this time to prevent disconnection from grid and stay connected to contribute during fault. UPQC is also used for fast restoration of system steady state, power factor improvement, prevent rotor over current.


Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6361
Author(s):  
Giovanni Artale ◽  
Giuseppe Caravello ◽  
Antonio Cataliotti ◽  
Valentina Cosentino ◽  
Dario Di Cara ◽  
...  

This paper presents a feasibility study on how to implement power quality (PQ) metrics in a low-cost smart metering platform. The study is aimed at verifying the possibility of implementing PQ monitoring in distribution networks without replacing existing smart metering devices or adding new modules for PQ measurements, thus zeroing the installation costs. To this aim, an electronic board, currently used for remote energy metering, was chosen as a case study, specifically the STCOMET platform. Starting from the specifications of this device, the possibility of implementing power quality metrics is investigated in order to verify if compliance with standard requirements for PQ instruments can be obtained. Issues related to device features constraints are discussed; possible solutions and correction algorithms are presented and experimentally verified for different PQ metrics with a particular focus on harmonic analysis. The feasibility study takes into account both the use of on-board voltage and current transducers for low voltage applications and also the impact of external instrument transformers on measurement results.


2014 ◽  
Vol 543-547 ◽  
pp. 878-883
Author(s):  
Jun Dong ◽  
Jian Guo Xu ◽  
Hao Zhang ◽  
Yu Jie Pei ◽  
Xian Feng Li

The cause serious deterioration in power quality problems for the growing impact and nonlinear load capacity, introduced SVC device in the role of modern power systems and applications. According to the lack of adequate regional dynamic reactive power regulation means to cause voltage fluctuations, harmonics exceeded the actual situation, through analysis and simulation of the existing 66kV grid power quality conditions, refers to the necessity of application of SVC, the compensation capacity for SVC, filter capacitor system parameters and control strategies were designed, the results show improved 220kV SVC reactive power flow distribution system, reducing the system once or twice a net loss, reducing the impact and harmonic interference voltage caused by nonlinear loads, system security, economic operation of great significance.


Power quality in power system is one of the most important researches in the recent age, many researchers working in this area keeping objective to achieve quality power. This paper presents power quality issues in power systems, especially in INDIA. It also includes the various causes of power quality problems, their impact and precautionary measure to solve the power quality issues. Various mitigating devices used to solve various power quality problems and some methods suggested improving the power quality. Different types of controller and their specific applications also presented. A Hybrid APF designee is also suggested to mitigate the harmonics in power lines. Finally, the paper is designed to give an overview of power quality phenomenon in power system and can be utilized by the researchers those working in the area of power quality.


This paper presents the simulation-based study and results of a three-phase shunt active power filter (SAPF) for power quality improvement. The power quality of the power systems is degraded because of the presence of non-linear loads at the consumer end. The SAPF can reduce the impact of harmonics caused by the non-linear loads. The analyzed SAPF system is modeled and simulated using MATLAB-Simulink workspace. The ultimate goal of this study is to improve the total harmonic distortion of the system as per the standards defined by IEEE-519.


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