An Improved Fast Harmonic Load Flow Method for Distribution Network Considering Distributed Generators

Author(s):  
Zheng-Rui Peng
Author(s):  
Yuntao Ju

With large-scale distributed generators (DGs) in an active distribution network (ADN), conventional load flow convergence failure is incurred by heavy power transmission. The Holomorphic Embedding Load Flow Method (HELM) has proven to be more robust than the Newton–Raphson method under heavy power transmission. At present, HELM is mainly designed for balanced transmission networks. In this study, we developed a three-phase HELM model to accommodate DGs, delta connection loads, and ZIP loads for ADN. The effectiveness and better performance of the proposed method under heavy load situations were validated using modified unbalanced IEEE 13, 34, 37, and 123 test feeders.


2021 ◽  
Vol 11 (4) ◽  
pp. 7311-7320
Author(s):  
I. C. Barutcu

Harmonic penetration can be problematic by the growing interconnection of Wind Turbines (WTs) in distribution networks. Since the active power outputs of WTs and loads in the distribution system have uncertainties, the optimal WT penetration level problem can be considered to have a stochastic nature. In this study, this problem is taken into account in the stochastic optimization method with the consideration of uncertainties in wind speed and distribution network load profile. Chance constraint programming is taken into account in the determination of optimal WT penetration levels by applying the Genetic Algorithm (GA) along with Monte Carlo Simulation (MCS). The harmonic power flow analysis based on the decoupled harmonic load flow approach is employed in the distorted distribution network. Chance constraints are considered for the harmonic issues such as the Total Harmonic Distortion of Voltage (VTHD), Individual Harmonic Distortion of Voltage (VIHDh), and Root Mean Square of Voltage (VRMS).


The Distributed generation and fast operating power electronic devices are attracting more attention due to their effective solution for improvement in the voltage profile, to meet the increasing power consumption, reduction in the power loss, enhancement in the power transfer capacity of the transmission lines, reducing the overloading of the entire network. The optimal placement of DG and FACTs devices plays key role in improvement of the network reliability and voltage stability. In this paper exhaustive load flow analysis is carried out for optimal placement of DG and UPFC. The proposed method is tested on 40 bus distribution network. The obtained results are satisfactory in terms of improvement in the overall performance of the distribution network.


Author(s):  
Yuntao Ju ◽  
Fuchao Ge ◽  
Yi Lin ◽  
Jing Wang

Open source software such as OpenDSS has given a lot of help to distribution network researchers and educators. With high penetration of distributed renewable energy resources into distribution network, tradition distribution steady state analysis software such as OpenDSS is faced with difficulty in handling distributed generators. Three-phase distributed generators are often modeled in sequence frame while unbalanced distribution network are usually modeled in phase frame. So a load flow in sequence-phase coupled frame is proposed to handle models described in both frames. Voltage controlled DGs which are difficult to cope with in OpenDSS are handled in proposed program. The steady state analysis platform is programmed with open source Modelica language and the main aim of this paper is to introduce an open source platform for active distribution network steady analysis include load flow and short circuit analysis which can be easily adopted and improved by other educators and researchers.


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