A.S. Mokhtar

MATLAB/Simulink based modeling and simulation of power quality disturbances

The continuous monitoring of power quality (PQ) disturbances in electrical power distribution system has become an important issue for utilities and customers. The power system operation can be improved and maintained by analyzing the PQ disturbances systematically. In this paper, an attempt has been made to review the modeling and simulation of the PQ disturbances due to the exploitation of various types of loads. The PQ disturbances are created by using parametric equations as well as electrical power distribution system models in MATLAB/SIMULINK environment. The PQ disturbances of voltage magnitude variation such as sag, swell and interruption are created by applying different types of faults and heavy load in the power distribution model. The frequency variation types of PQ disturbances like harmonics are generated by applying power electronic converter. The non-stationary or transient PQ disturbances are produced by applying a capacitor switching bank in distribution model. The results of PQ disturbance waveforms obtained by both techniques are very similar to realtime PQ signals. The PQ waveforms obtained are suitable for checking the performance of the new automatic classification algorithms.

Controlling and modeling power-electronic interface DERs in islanding mode operation micro grid

Distributed energy resources (DERs) such as micro turbine, wind turbine, fuel cell, photovoltaic system and so on, which are high-efficient, high quality and high reliable electrical sources, are been able to create flexible control on power generation during the islanded mode operation of micro grid by power-electronic interface. Performances of two types of inverter controller (PQ controller and VSI controller) show the important role of each model in balancing and power sharing within the islanded network. PQ controller prepares constant active power at specified power factor and VSI controller regulates frequency and voltage through system. This paper is prepared to model two kinds of controller and then investigated the role of controllers through changing load demand and output power of DERs during the islanded network. Moreover appropriate method for handling DERs such as PQ and VSI controller will be proposed in a simulation program which is developed using MATLAB® for one case study. The results are shown and compared in an abbreviated manner.

Steady-state behavior of distributed energy resources in unbalance radial active distribution networks

Unbalance radial active distribution network (URADN) is the combination of unbalance radial distribution network and distributed energy resources (DERs) such as micro sources, wind turbines, fuel cell, photovoltaic system, etc. Regarding to unbalance structure, different kinds of DERs models and bidirectional power flow, some network parameters such as amplitude voltage, percent unbalance voltage, and power losses of network will alter accordingly. The complexity of URADN will be more when different kinds of DERs are allocated. So investigating the behavior of DER models in URADN is necessary. A suitable power flow analysis will provide a platform to analyze these behaviors in steady state condition. This paper offers suitable models for URADN components such as loads, lines, DERs and so on according to their structure and operation. Moreover appropriate method for handling DERs such as PV and PQ nodes will be proposed in a Power flow program which is developed using MATLAB® for two practical case studies. The results are shown and compared in an abbreviated manner.

Impact of fixed-speed wind turbine farm on radial distribution network

This paper presents the result of development wind farm as unpredictable renewable energy resource in radial distribution network. Wind farm consists of pitched regulated fixed-speed wind turbine which is developed in 24-hour forward-backward sweep load flow analysis. Through load flow analysis, some parameters of network such as voltage profiles, total real power fed of substation and total power loss are calculated for each internal period hour of day. Procedure for capacity allocation of wind farm is determined by both network and wind turbine characteristics for one hourly wind speed for one day. The proposed method is developed for one case-study using MATLAB® software. The results are shown and compared in an abbreviated manner.

Small signal stability analysis of rectifier-inverter fed induction motor drive for Microgrid applications

This paper presents a small signal model of a rectifier-inverter fed induction motor drive system by neglecting the effect of stator voltage harmonics. All dynamic equations are obtained by linearization about an operating point. The dynamic of DC link between rectifier and inverter and variations in voltage and frequency of the network side is also considered in this study. The investigation of the stability shows the system is stable during dynamic and steady state conditions and oscillatory modes are well damped. This model can be used as dynamic load in stability analysis of Microgrid

Automatic pattern recognition of single and multiple power quality disturbances

Abstract The automatic pattern recognition of single and multiple power quality (PQ) disturbances is a very important task for the detection and monitoring of multiple faults and events in electrical power system. This paper presents an automatic classification algorithm for PQ disturbances based on wavelet norm entropy features and probabilistic neural network (PNN) as an effective pattern classifier. The proposed method employs the discrete wavelet transform based on multi-resolution analysis technique to extract the most important and constructive features of PQ disturbances at various resolution levels. The distinctive norm entropy features of the PQ disturbances have been extracted and were employed as inputs to the PNN. Various other architectures of artificial neural network such as multilayer perceptron and radial basis function neural network have also been employed for comparison. The PNN is found the most suitable pattern recognition tool for the classification of the PQ disturbances. Various PQ disturbances used for analysis were generated by simulating a typical 11-kV distribution system. The simulation results obtained show that the proposed approach can detect and classify the PQ disturbances effectively and can be implemented successfully in real-time electrical power distribution networks.

Automatic classification of single and hybrid power quality disturbances using Wavelet Transform and Modular Probabilistic Neural Network

Power Quality (PQ) monitoring in a systematic and automated way is the important issue to prevent detrimental effects on power system. The development of new methods for the automatic classification of PQ disturbances is at present a major concern. This paper presents a novel approach of automatic detection and classification of single and hybrid PQ disturbances using Discrete Wavelet Transform (DWT) and Modular Probabilistic Neural Network (MPNN). The automatic classification of the PQ disturbances consists of three stages i) data generation, ii) feature extraction and iii) disturbance classification. The data is generated by synthetic models of single and hybrid PQ disturbance signals based on IEEE 1159 standard. DWT with multiresolution analysis was applied for feature extraction from the PQ waveforms. The entropy and energy features extracted from the detail and approximation coefficients were applied as the training and testing data to MPNN in order to accomplish the automatic classification process. The effectiveness of the proposed algorithm has been validated by using a typical real-time underground distribution network in Malaysia which was simulated in PSCAD/EMTDC power system software to generate PQ disturbances. The simulation results show that the classifier has an excellent performance in terms of accuracy and reliability even in the case of PQ signals under noisy condition.

Automated Meter Reading and Advanced Metering Infrastructure projects

Two communication media between meter and server are applicable in Electrical Distribution Company (EDCO) in Jordan, namely, the Power Line Carrier (PLC) and the General Packet Radio Service (GPRS). In this paper, we discuss the implementation of these two communication media in the Automated Meter Reading (AMR) and the Advanced Metering Infrastructure (AMI) project in Jordan; and also point-out the main advantages and dis-advantages of using such grid of AMR/AMI based on these communication media.

Elimination of total harmonic distortion in transmission lines using adaptive fuzzy logic in de-icing process

This paper mostly focuses on a thermal DC deicing method using a critical current. The thermal heat that is induced when this current flows in the conductor is used to milt the ice. The DC deicing is selected since it does not need a large amount of reactive power. This paper explains the heat process as a balance heat transferring process. The proposed model uses two methods to reduce the harmonic distortion that is produced during the melting process, these methods are: AC filter and fuzzy logic controller. DC deicing model is designed and simulated using the MATLAB/SIMULINK program by four substations with 220KV. The 35KV station which is the ice melting power is chosen; the equivalent reactance is 0.01H, with a line length 100 km and quality factor 20, as a general case. The results show how the design is effective to reduce the harmonic distortion using filter. Based on changing the proposed parameters on the SIMULINK model, different outputs are resulted where each one has an obvious effect on the DC current.