Aida Fazliana Abdul Kadir

Integrating Photovoltaic Systems In Power System : Power Quality Impacts And Optimal Planning Challenges

This paper is an overview of some of the main issues in photovoltaic based distributed generation (PVDG). A discussion of the harmonic distortion produced by PVDG units is presented. The maximum permissible penetration level of PVDG in distribution system is also considered. The general procedures of optimal planning for PVDG placement and sizing are also explained in this paper. The result of this review shows that there are different challenges for integrating PVDG in the power systems. One of these challenges is integrated system reliability whereas the amount of power produced by renewable energy source is consistent. Thus, the high penetration of PVDG into grid can decrease the reliability of the power system network. On the other hand, power quality is considered one of the challenges of PVDG whereas the high penetration of PVDGs can lead to more harmonic propagation into the power system network. In addition to that, voltage fluctuation of the integrated PVDG and reverse power flow are two important challenges to this technology. Finally, protection of power system with integrated PVDG is one of the most critical challenges to this technology as the current protection schemes are designed for unidirectional not bidirectional power flow pattern.

Low voltage ride through capability of fuel cell generation system connected to low voltage network

New grid code is expected to require distributed generation units operating parallel with the low voltage grid to ride through low voltage event and at the same time injecting reactive current into the grid. The paper discusses and highlights the problems that could arise and explores the solutions to mitigate these problems. Simulation results show that a fuel cell generation system (FCGS) is not able to ride through very low voltage events with its standard power conditioner without operating within its design limit. Additional devices have to be included to enable continuous operation during this severe low voltage event. In meeting the requirement of reactive power support, an additional fast voltage control loop has to be added to its line side converter control. With the improvement inside its power conditioner circuit and controller, simulation results demonstrate that FCGS is capable of riding zero voltage events while at the same time adhering to new grid code requirements.

An improved gravitational search algorithm for optimal placement and sizing of renewable distributed generation units in a distribution system for power quality enhancement

Distributed generation (DG) is an important element to be considered in distribution planning since it plays a major role in stability and power quality improvement. This paper presents a new method for determining optimal sizing and placement of DG in a distribution system. A multi-objective function is formed to minimize the total losses, average total voltage harmonic distortion, and voltage deviation in the distribution system. The improved gravitational search algorithm (IGSA) is proposed as an optimization techniques and its performance is compared with other optimization techniques such as particle swarm optimization (PSO) and GSA. The load flow algorithm from MATPOWER and harmonic load flow was integrated in MATLAB environment to solve the proposed multi-objective function. Finally, the proposed algorithm is tested on the radial 69-bus distribution system with three case studies. The results show that the IGSA performs better than PSO and GSA by giving the best fitness value and the fastest average elapsed time.

Development of learning object for engineering courses in UTeM

This paper views e-learning initiative in UTeM with a focus on the development of learning object for engineering courses in UTeM. Having a learning management system called SPeL, UTeM further promote e-learning culture by encouraging knowledge sharing through SPeLs learning object repository. UTeM is gradually building a collection of reusable learning objects to be shared across faculties. The paper discusses the concept of learning object in UTeM context, roles of Subject Matter Expert (SME), UTeMs learning object design strategy and the development stages of learning object in UTeM. The paper further stated briefly on the benefits of learning object to UTeM.

The impacts of distributed Photovoltaic generation on power distribution networks losses

The maximum allowable penetration level of Photovoltaic-based distributed generation (PVDG) is one of the major concerns in power system. It gives significant impacts since PVDG might inject positive and negative effects to the distribution system. In this regard, this paper investigates the relationship between PVDG injections on distribution system and system losses. Three different IEEE test systems have been considered in this work, namely IEEE 13 bus, IEEE 30 bus and IEEE 69. Each test system consists of four simulation cases in order to determine the effect of PVDG on the systems losses under various penetration levels. PVDG is injected at different buses connected to different load values. The optimum penetration level is based on the systems power losses. The penetration level must not exceed the maximum boundary in term of total losses for the systems to maintain its efficiency and reliability.

Optimal Placement and Sizing of Renewable Distributed Generation via Gravitational Search Algorithm

The installation of distributed generation (DG) gives advantages to the environment such as, it contribute in the reduction of non-peak operating cost, diversification of energy resources, lower losses thus improving overall organization. These advantages might be rescinded if no proper location and sizing of DGs are considered before the DG’s installation. This paper offers an optimal location and sizing of multiple DGs using heuristic method called gravitational search algorithm (GSA). The suggested algorithm is tested on 13-bus radial distribution system. This method is being compared with particle swarm optimization (PSO) in terms of system power loss, voltage deviation and total voltage harmonic distortion (THDv). GSA shows the ability to locate and sized DG optimally with a better performance and more reliable than PSO.

Sustainable Environmental Economic Dispatch Optimization with Hybrid Metaheuristic Modification

Received Dec 04, 2017 Revised Jan 11, 2018 Accepted Apr 15, 2018 Wireless Body Area Networks (WBANs) are fundamental technology in health care that permits the information of a patient’s essential body parameters to be gathered by the sensors. However, the safety and concealment defense of the gathered information is a key uncertain problem. A Hybrid Key Management (HKM) scheme [13] is worked based on Public Key Cryptography (PKC)-authentication scheme. This scheme uses a oneway hash function to construct a Merkle Tree. The PKC method increase the computational complexity and lacking scalability. Additionally, it increases expensive computation, communication costs and delay. To overcome this problem, Robust Security for Protected Health Information by ECC with signature Hash Function in WBAN (RSP) is proposed. The system employs hash-chain based key signature technique to achieve efficient, secure transmission from sensor to user in WBAN. Moreover, Elliptical Curve Cryptography algorithm is used to verifies the authenticate sensor. In addition, it describes the experimental results of the proposed system demonstrate the efficient data communication in a network.A Weblogs contains the history of User Navigation Pattern while user accessing the websites. The user navigation pattern can be analyzed based on the previous user navigation that is stored in weblog. The weblog comprises of various entries like IP address, status code and number of bytes transferred, categories and time stamp. The user interest can be classified based on categories and attributes and it is helpful in identifying user behavior. The aim of the research is to identifying the interested user behavior and not interested user behavior based on classification. The process of identifying user interest, it consists of Modified Span Algorithm and Personalization Algorithm based on the classification algorithm user prediction can be analyzed. The research work explores to analyze user prediction behavior based on user personalization that is captured from weblogs.Wireless Body Area Networks (WBANs) are fundamental technology in health care that permits the information of a patient’s essential body parameters to be gathered by the sensors. However, the safety and concealment defense of the gathered information is a key uncertain problem. A Hybrid Key Management (HKM) scheme [13] is worked based on Public Key Cryptography (PKC)-authentication scheme. This scheme uses a oneway hash function to construct a Merkle Tree. The PKC method increase the computational complexity and lacking scalability. Additionally, it increases expensive computation, communication costs and delay. To overcome this problem, Robust Security for Protected Health Information by ECC with signature Hash Function in WBAN (RSP) is proposed. The system employs hash-chain based key signature technique to achieve efficient, secure transmission from sensor to user in WBAN. Moreover, Elliptical Curve Cryptography algorithm is used to verifies the authenticate sensor. In addition, it describes the experimental results of the proposed system demonstrate the efficient data communication in a network.

Optimal allocation and sizing of photovoltaic-based distributed generation for voltage dip improvement

Voltage dips in distribution system network is one of the power quality event that need to be taken into account since it will effect the system performance in delivering energy to the consumers and load. Hence, photovoltaic-based distributed generation (PVDG) is an alternative way in ensuring the system stability and enhancing the power quality. This paper investigates the impact of PVDG units installation with the average dip amplitude (VDA) of the system. The research concentrated on voltage dips due to three-phase faults at all the systems buses. The fault position method (FPM) is being utilized for the assessment of the voltage dip in the distribution system. An improved gravitational search algorithm (IGSA) aid in the searching of the optimum locations and sizes of PVDG units. The results shows that IGSA provide a better solution with the highest performance compared to particle swarm optimization (PSO). The optimization technique is being tested on IEEE 13-bus radial in MATLAB environment. The system experienced fewer dips after the placement of PVDG units.

Performance verification of real-time harmonic sources identification system

This paper presents the performance verification of accuracy between simulation and real-time harmonic source identification system. The simulation and real-time system are implementing spectrogram as analysis technique that offers high accuracy and represent signals in time-frequency representation (TFR). From the TFR, signal parameters such as instantaneous of root mean square (RMS), fundamental RMS, total harmonic distortion (THD), total non-harmonic distortion (TnHD) and total waveform distortion (TWD) are estimated. Then, the location of harmonic sources is determined by observing the significant characteristics between fundamental and harmonic impedances. The prediction accuracy of a forecasting method which is mean absolute percentage error (MAPE) is used in performance verification of accuracy. The small difference of 0.008% of average MAPE measured between the simulation and real-time system shows that the real-time system gives a high accuracy measurement. Furthermore, the real-time system also able to identify the location of harmonic sources with 100% correct identification of harmonic sources similar to simulation. Hence, it is proven that the real-time system is accurate and reliable enough to perform harmonic sources identification.

Harmonic Performance of Grid-Connected PV System under Various Penetration Levels

This paper studies the harmonic performance of grid-connected PV system under various penetration levels. The system under study was modelled in MATLAB/Simulink environment. Current and voltage distortions were studied in terms of the percentage of Total Harmonic Distortion (THD) under different PV penetration scenarios. The results showed that the Grid-Connected PV generates a different level of harmonics distortion depending on the PV penetration level that was injected to the grid.