Single phase load balancing in a three phase system at distribution and unit level

Author(s):  
Michella Fahim ◽  
Moustapha El Hassan ◽  
Maged B. El Najjar
2019 ◽  
Vol 16 (3) ◽  
pp. 289-310 ◽  
Author(s):  
Vinay Naguboina ◽  
Satish Gudey

In this work, a Three phase Transformerless Hybrid Series Active Power Filter (THSeAF) based on Sliding Mode Control (SMC) is proposed to mitigate the voltage and current distortions present in an electrical distribution systems (EDS). A Sliding Mode Controller is designed by controlling the parameters present on the load side as well as source side of the system. Three separate voltage source converters (VSC) are used. The mod1elling of the system is derived by considering a single-phase system by using state space analysis. The frequency response characteristics have been derived for the single-phase system and the stability of the system is studied. It is observed that the system has good stability margins when the SMC is applied at the source side compared to load side. Simulation results obtained in PSCAD/EMTDC v4.6 have been observed for power quality issues like voltage sags, voltage swells, voltage distortions, voltage unbalances and their concurrent occurrence. The approach of stationary reference frame was used for source side control and PQ theory is used for load side control. It is observed that the proposed controller works well in obtaining a stable and constant load voltage during these power quality issues. The difference in settling time observed is around 4 ms for the load side and source side control. The THD present in the load voltage is near about 1%. The SMC is found to be robust in obtaining a constant load voltage with low THD and an improved power factor.


2021 ◽  
Vol 31 (08) ◽  
pp. 2150118
Author(s):  
Ali̇ Durdu ◽  
Yilmaz Uyaroğlu

In this study, a chaos-theoretic method is proposed to model the case of ferroresonance that can occur under nominal conditions in power systems, and the factors that determine the types of ferroresonance to occur are examined. In the ferroresonance chaotic system modeled in Matlab environment, the length of the transmission line and the breaker capacities in the circuit are fixed and its relationship with the transformer efficiency is investigated. In the proposed chaotic modeling, considering the situations that may occur in practical applications, the ferroresonance situations that occur when the single-phase remains open in the three-phase system are examined. In the study, ferroresonance, which occurs when one phase is open in a three-phase system, is analyzed by considering the situations that may happen during practical implementations. The similarity between the mathematical expressions obtained from the systems that create ferroresonance and Duffing oscillator is evaluated. In the chaotic system, fundamental ferroresonance, subharmonic ferroresonance, and chaotic ferroresonance situations are created depending on the transformer loss. Additionally, ferroresonance that occurs when the chaotic system is of fractional-order is analyzed, and it is observed that results of ferroresonance with different fractional-order values are not different. The results show that transformer loss is a significant element to determine the type of ferroresonance in power transformers. Also, when the chaotic system is operated in the fractional-order setting, the ferroresonance cases that occur are re-examined, and it is observed that the system can exit from the chaotic situation and prevent the formation of ferroresonance when fractional-order control is applied. According to the results, the fractional-order method can be used to control ferroresonance.


2014 ◽  
Vol 521 ◽  
pp. 288-291
Author(s):  
Yu Sheng Quan ◽  
Xin Zhao ◽  
Hua Gui Chen ◽  
En Ze Zhou

Based on the method of symmetrical components of D, 11 and Y, o distribution transformer coupling two different effects of different magnetic circuit coupled to the three-phase system with a system-generated analysis and comparison. Analysis of the difference between the two groups of different connections on the transformer structure. Described in the single-phase short circuit fault clearing, 3n harmonic current suppression and affordability aspects of single-phase unbalanced load, D, ll coupling transformers are significantly better than Y,0 coupling transformer. This has necessarily important for the study of energy loss reduction.


Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1542
Author(s):  
Hyun-Jun Lee ◽  
Dae-Shik Lee ◽  
Young-Doo Yoon

This paper proposes a new unified power flow controller (UPFC) topology. A single phase of them system with the proposed topology consists of an N:2 transformer with a center tap at the low-voltage side and a power converter module comprising full- and half-bridge converters. A three-phase system can be implemented with three devices. While the conventional UPFC topology uses two three-phase transformers, which are called series and parallel transformers, the proposed topology utilizes three single-phase transformers to implement a three-phase UPFC system. By using an autotransformer structure, the power rating of the transformers and the voltage rating of switches in the power converter module can be significantly decreased. As a result, it is possible to reduce the installation spaces and costs compared with the conventional UPFC topology. In addition, by adopting a full- and half-bridge converter structure, the proposed topology can be easily implemented with conventional power devices and control techniques. The techniques used to control the proposed topology are described in this paper. The results obtained from simulations and experiments verify the effectiveness of the proposed UPFC topology.


Author(s):  
Hitendra Singh Thakur ◽  
Ram Narayan Patel

For the three phase power electronic and drive applications, vector control or the synchronous reference frame (SRF) based control concept is well accepted and settled amongst the research communities. Although the SRF concept has gained popularity and appreciation in developing the three phase controllers, still the concept has not reached the same level in case of a single phase system. The work presented in this paper is mainly concerned to the design of a hybrid Artificial Neural Network and Fuzzy Logic based controller for a single phase stand-alone photo-voltaic (PV) power system. The adaptive neuro fuzzy inference system (ANFIS) controller proposed in this paper is chiefly meant for improving the transient and steady state responses; for minimizing the distorting effect of the low order load current harmonics encountered particularly in case of switching the drive based inductive loads and to help maintain the inverter output voltage constant under different loading circumstances. The result obtained through simulation work, shows the effectiveness of the proposed controller as compared with the previously established research works.


2021 ◽  
Vol 19 ◽  
pp. 137-142
Author(s):  
K. Karam ◽  
◽  
M. Badawi El Najjar ◽  
M. El Hassan

The pervasion of transformerless grid connected photovoltaic (PV) inverters has triggered the concerns of many researchers since it can induce power quality problems. In these types of applications, the generation of common mode (CM) leakage current is one of the major factors that affects the reliability of the overall design. In single-phase systems, the concept of the common ground between the PV negative terminal and the neutral point of the grid is the only topology that “totally” cancels this CM noise. However, none of the existing three-phase inverter techniques is able to totally remove it. Therefore, this paper proposes a three-phase PV inverter based on the concept applied in the single-phase system in order to achieve, for the first time, a zero CM noise in three-phase grid-connected PV applications. The proposed inverter is simulated with a PV array, appropriate modulation technique, corresponding inverter controller, and a three-phase Y-connected alternating current (AC) grid voltage. The simulation of the overall system is done using Matlab/Simulink software. As compared with results of existing three-phase topologies, this is the only three-phase transformerless PV inverter technique that offers generation of multilevel output, total elimination of leakage current flow, simple inverter structure, and uncomplicated modulation technique.


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