scholarly journals Optimal Phase Arrangement of Distribution Transformers for System Unbalance Improvement and Loss Reduction

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 545 ◽  
Author(s):  
Chia-Sheng Tu ◽  
Ming-Tang Tsai
Keyword(s):  
Distribution System ◽  
Load Flow ◽  
Phase Selection ◽  
Customer Information ◽  
Distribution Transformers ◽  
Three Phase ◽  
Phase Combination ◽  
Line Loss ◽  
Operating Constraints ◽  
Selection Of

This paper presents an efficient strategy for transformer planning to reduce the system losses by means of transformer rearrangement. The customer connected to the distribution transformer are first investigated by the field survey, and the loads of the various customers are collected from the customer information system (CIS) and distribution database system (DAS) to derive their load patterns. The objective function is to minimize the total line loss in the 24 intervals. An improved bacterial foraging algorithm (IBFO) is proposed herein to find the optimal phase combination of distribution transformers to minimize the total line loss by considering operating constraints. A three-phase load flow program with Eeuivalent current injection (ECT) is used to solve the total line loss and system unbalance factor on a Taipower distribution system. The results can help operators not only perform the proper installation phase selection of distribution transformers, but also reduce the system losses, decrease the system unbalance factor, and improve the voltage profiles of the buses.

A Probability Method for Very Short-Term Steady State Analysis of a Distribution System with Wind Farms

2008 ◽  
Vol 9 (5) ◽  
Author(s):  
Antonio Bracale ◽  
Pierluigi Caramia ◽  
Guido Carpinelli ◽  
Pietro Varilone
Keyword(s):  
Steady State ◽  
Distribution System ◽  
Wind Farm ◽  
Probabilistic Method ◽  
Wind Farms ◽  
Load Flow ◽  
Probability Method ◽  
Short Term ◽  
Flow Equations ◽  
Three Phase

In this paper, a probabilistic method is proposed to analyze the very short-term steady-state performance of an unbalanced distribution electrical system characterized by the presence of wind farms. This method, which can take into account the uncertainties of loads and wind productions, is based on a Monte Carlo simulation procedure applied to the non-linear three-phase load flow equations, including wind farm models. Bayesian time series models are used to predict the next hour's wind speed probability density functions, making possible a predictive evaluation of the very short-term system steady-state behavior. Numerical applications are presented and discussed with reference to the three-phase unbalanced IEEE 34-bus test distribution system in the presence of wind farms connected at different busbars.

scholarly journals A new method to incorporate three-phase power transformer model into distribution system load flow analysis

2021 ◽  
Vol 10 (3) ◽  
pp. 262
Author(s):  
Rudy Gianto ◽  
Purwoharjono Purwoharjono
Keyword(s):  
Distribution System ◽  
Power Transformer ◽  
Flow Analysis ◽  
Test System ◽  
Load Flow ◽  
Simple Method ◽  
System Load ◽  
Load Flow Analysis ◽  
Three Phase ◽  
Transformer Model

This paper proposes a new and simple method to incorporate three-phase power transformer model into distribution system load flow (DSLF) analysis. The objective of the present work is to find a robust and efficient technique for modeling and integrating power transformer in the DSLF analysis. The proposed transformer model is derived based on nodal admittance matrix and formulated by using the symmetrical component theory. Load flow formulation in terms of branch currents and nodal voltages is also proposed in this paper to enable integrating the model into the DSLF analysis. Singularity that makes the calculations in forward/backward sweep (FBS) algorithm is difficult to be carried out. It can be avoided in the method. The proposed model is verified by using the standard IEEE test system.

Modeling of Synchronous Generator and Full-scale Converter for Distribution System Load Flow Analysis

2021 ◽  
Author(s):  
Inderpreet Singh Wander
Keyword(s):  
Distribution System ◽  
System Analysis ◽  
Synchronous Generator ◽  
Test System ◽  
Load Flow ◽  
Green Energy ◽  
Full Scale ◽  
Control Mode ◽  
Proposed Model ◽  
Three Phase

Environmental awareness and the need to reduce greenhouse gas emissions have promoted the use of green energy sources such as Wind Energy Conversion Systems (WECS). The Type 4 Permanent Magnet Synchronous Generator (PMSG) with a Full-Scale Converter has grown to be a preferred choice among WECS. Conventionally these WECS are modeled as fixed PQ injections in distribution system analysis studies and for that reason they are not accurately represented. This inaccuracy is accentuated given the large-scale of integration of WECS. To overcome this limitation, this thesis proposes to develop a steady-state model for the Type 4 PMSG WECS to be used in unbalanced three-phase distribution load flow programs. The proposed model is derived from the analytical representation of its six main components: (1) the wind turbine, (2) the synchronous generator, (3) the diode-bridge rectifier, (4) voltage source inverter, (5) the dc-link with a boost converter that connects them, and (6) control mode action. This proposed model is validated through mathematical analysis and by comparing with a Matlab/Simulink model. Subsequently, the proposed model is integrated into a three-phase unbalanced load flow program. The IEEE 37-bus test system data is used to benchmark the results of the power flow method.

scholarly journals Optimal setting of DOC relay in distribution system in presence of D-FACTS

2021 ◽  
Vol 10 (4) ◽  
pp. 1811-1818
Author(s):  
Lazhar Bougouff ◽  
Abdelaziz Chaghi
Keyword(s):  
Power Distribution ◽  
Distribution System ◽  
Electrical Power ◽  
Dial Setting ◽  
Facts Devices ◽  
Three Phase ◽  
Network Operation ◽  
Optimal Setting ◽  
Selection Of ◽  
Optimal Settings

The process of selecting optimal settings for directional over-current relays (DOC relays) is a selection of time dial setting (TDS) and IP (backup current), So that changes in the system of electrical power distribution. In this work, a breeder genetic algorithm (BGA) has been applied to optimal settings of DOC relays with multisystem D-FACTS devices. The simulation consists of two network operation scenarios, scenario without D-FACTS which consisting of coordination of DOC relays against three phase faults, and the second scenarios with multi TCSC. In general, had been verified on optimal settings of relays that the impacts of TCSC insertion in 33-bus distribution system on DOC relays.

A three-phase linear load flow solution based on loop-analysis theory for distribution system

2019 ◽  
Vol 38 (2) ◽  
pp. 703-723 ◽  
Author(s):  
Hong wei Li ◽  
Hairong Zhu ◽  
Li Pan
Keyword(s):  
Linear Approximation ◽  
Distribution System ◽  
Load Flow ◽  
Loop Analysis ◽  
Content Type ◽  
Flow Solution ◽  
Flow Method ◽  
Analysis Theory ◽  
Linear Load ◽  
Three Phase

Purpose To realize the operation optimizing of today’s distribution power system (DPS), like economic dispatch, contingency analysis, and reliability and security assessment etc., it is beneficial and indispensable that a faster linear load flow method is adopted with a reasonable accuracy. Considering the high R/X branch ratios and unbalanced features of DPS, the purpose of this paper is to propose a faster and non-iterative linear load flow solution for DPS. Design/methodology/approach Based on complex function theory, the derivations of the injection current linear approximation have been proposed for the balanced and the single-, double- and three-phase unbalanced loads of DPS on complex plane. Then, a simple and direct linear load flow has been developed with loop-analysis theory and node-branch incidence matrix. Findings The methodology is appropriate for balanced and single-, double- and three-phase hybrid distribution system with different load models. It provides a fast and robust load flow method with a satisfactory accuracy to handle the problems of DPS whenever the load flow solutions are required. Research limitations/implications The distributed generators (DGs) with unity or fixed power factors can be easily included. But the power and voltage nodes cannot be dealt with directly and need to be further studied. Originality/value By combining the current linear approximation with the loop theory-based method, a new linear load flow method for DPS has been proposed. The method is valid and acute enough for balanced and unbalanced systems and has no convergent problems.

scholarly journals An Optimal Phase Arrangement of Distribution Transformers under Risk Assessment

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5852
Author(s):  
Chia-Sheng Tu ◽  
Chung-Yuen Yang ◽  
Ming-Tang Tsai
Keyword(s):  
Distribution System ◽  
Value At Risk ◽  
Power Flow ◽  
Distribution Systems ◽  
Operating Efficiency ◽  
Voltage Profile ◽  
Distribution Transformers ◽  
Line Loss ◽  
Load Arrangement ◽  
Phase Arrangement

This paper presents a phase arrangement procedure for distribution transformers to improve system unbalance and voltage profile of distribution systems, while considering the location and uncertainties of the wind turbine (WT) and photovoltaics (PV). Based on historical data, the Monte Carlo method is used to calculate the power generation value-at-risk (VAR) of WTs/PVs installed under a given level of confidence. The main target of this paper is to reduce the line loss and unbalance factor during 24-hour intervals. Assessing the various confidence levels of risk, a feasible particle swarm optimization (FPSO) is proposed to solve the optimal location of WTs/PVs installed and transformer load arrangement. A three-phase power flow with equivalent current injection (ECI) is analyzed to demonstrate the operating efficiency of the FPSO in a Taipower feeder. Simulation results will support the planner in the proper location of WTs/PVs installed to reduce system losses and maintain the voltage profile. They can also provide more risk information for handing uncertainties when the renewable energy is connected to the distribution system.

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