H. Hashim

Under frequency load shedding (UFLS): Principles and implementation

Under frequency load shedding is implemented to restore power system frequency stability if system frequency drops below the operational set point during major disturbance such as lost of generation. Different countries/utility companies have their own philosophies in implementing the under frequency load shedding scheme. Generally, it is based on country/utility requirements, e.g. the overall power system network and the countrys demographic. This paper presents the principles and implementation of the under frequency load shedding (UFLS) and presented using simulations of 56 test bus-system. The performance of the developed schemes under various conditions of disturbance were compared and analyzed. All the simulation works were performed using Siemens PTI software PSS®E.

Study of static voltage stability index as an indicator for Under Voltage Load Shedding schemes

Under Voltage Load Shedding (UVLS) has been successfully deployed in many systems throughout the world to protect local systems from voltage collapse. This is particularly true if the system conditions and the contingencies leading to voltage instabilities are of low probability, but would result in serious consequences. However, the locations and how much load to shed requires expert knowledge and experience working with the power grid. This paper will present on utilizing an established index called FVSI (Fast Voltage Stability Index) to act as a numerical verification of the shedding locations. The research work done shows that the FVSI index can be used and load shedding at these points does improve the stability of the system.

Optimization of mechanical input power to synchronous generator based on Transient Stability Center-of-Inertia: COI angle and COI Speed

Rotor angle of the machine may accelerate or decelerate due to transient instability depending on the mechanical power or the turbine power, Pm and electrical power, Pe. As such, injecting an appropriate mechanical input power in accordance to the electrical power demand and losses at a critical time and condition will avoid major supply interruption due to unnecessary tripping of circuit breaker during transient instability. This paper presents Evolutionary Programming (EP) approach to optimize the mechanical input power in order to prevent transient instability in the system. The optimization is based on Area-based COI-referred Transient Stability Indexes: COI Angle and COI Speed, for a three area system with six generators. Results obtained from the experiment revealed that the EP approach is able to give an optimal solution.

An analysis of Transient Stability using Center-of-Inertia: Angle and speed

Instability in the system may cause the rotor angle of the machine to accelerate or decelerate depending on the mechanical power and electrical power; most seriously could result to tripping of the machine This paper evaluates the impact of disturbances and types of loads to system stability using Area-based COI-referred Transient Stability Indexes: COI angle and COI speed. The analysis is carried out using PSS®E 32 software on IEEE 118 Bus Test System at system conditions with and without dynamic loads. The network is initially divided into significant areas based on the geographical.

A methodology to determine suitable placement of solar photovoltaic sources in the transmission system taking into account voltage stability index (VSI)

The integration of solar PVs which is projected to increase over the years creates concerns over stability. Reverse power flow occurs due to high PV penetration into the power system network. PV placement at proper locations in a transmission system is essential to maintain voltage stability. Improper placement will caused voltage stability of the system to be affected. However, if the PVs are connected at a strategic location it will lead to a more stable system. This paper presents a methodology for PV source placement in the transmission system while maintaining the stability of the. Voltage Stability Index (VSI) will be used as an indicator to measure the stability status of the system. Two test systems will be used for simulation for this research, the IEEE 30 Bus and 57 Bus Test System. The simulation results showed that proper placement of the PV source in the transmission system will lead to better stability to the system.

Effects of mechanical power fluctuation on power system stability

Fluctuation of mechanical power is known to be one of many major factors affecting stability of a power plant and the power system network connected to it. The occurrence of this fluctuation is due to the inconsistent input supply to the prime mover, mechanical failure and control system itself such as the process of quick operation of steam turbine governing, which would cause the pressure oscillation in turbine steam inlet pipeline. Consequences of this fluctuation may trigger situations such as power system low frequency oscillation and loss of synchronism, which can occur if the speed oscillation experienced by the machine exceeds its allowable limits. As a result, protection system will react, which causes the generator to be taken off line from the system. This paper presents the evaluation on the effects of mechanical power fluctuation on the power system stability based on turbine gain in static and dynamic load environment.

Adaptive protection for voltage instability mitigation scenario

Modern power system network are usually operated to its maximum capabilities. This in turn would expose the system towards possible voltage instability condition. Coupled with peak load condition where lines can be loaded to its limit, probable scenarios relating to voltage instability could lead to tripping of overload lines which would then lead to possible cascading tripping; ultimately lead towards voltage collapse condition. However, possible mitigating action is possible which could reduce the line loading and ultimately push the system back towards a voltage stable condition. This paper demonstrates a possibility of this occurring utilizing Fast Voltage Stability Index (FVSI) approaches to quickly assess the network voltage stability. Results show that these mitigating action does improve the stability of the system hence lead to a possible Wide Area Protection application which is synonymously linked to a smart grid system.

Changes in fault current levels due to renewable embedded generation in a distribution network

An increased interest in renewable energy such as wind, solar and etc. has reintroduced embedded generation to the power system network. However, traditional networks are designed for power to flow from the grid to the load. The integration of embedded generation into the system brought forth the issue of reverse power flow to system. A reverse flow of power would disrupt the operation of existing protection system in the network by changing the fault currents flowing in the line. This paper investigates the changes to the fault current and the effect of the integration of the embedded generation into existing power system networks. This research uses MATLAB/Simulink to simulate a simple test system network with embedded generation. Initial simulation result shows the reverse power flow lowers the value of the fault current from the grid. This results in a longer tripping time for existing overcurrent relays and possibly disruptions to the coordination of the protection system in the network.

Weak area analysis based on the apparent impedance and voltage indices

Heavily loaded condition may lead to power system instability either due to sudden increase in load or tripping of adjacent transmission line. When load increases, the apparent impedance decreases accordingly depending on the nature of load, similar instances can be observed during short circuit event [1, 2]. In addition, the system may also experience voltage instability originating from high power flow through the transmission line during fault and line outage condition. Hence, the ability for the system to quickly indicate possible voltage instability via fast voltage indicator is important in mitigating voltage instability from being further aggravated. Undesirable disconnection of transmission lines should also be avoided during voltage instability, while load encroachment possibilities into protective zone may cause unnecessary line isolation, which would result in cascading tripping [3, 4]. This paper presents the correlation between the apparent impedance calculated from different contingency scenario and the derived voltage indicator applied to the IEEE 30 Bus Test System.

Analysis on the Impact of Renewable Energy to Power System Fault Level

Received Mar 3, 2018 Revised Apr 11, 2018 Accepted Apr 21, 2018 Paintball has gained a huge popularity in Malaysia with growing number of tournaments organized nationwide. Currently, Ideal Pro Event, one of the paintball organizer found difficulties to pair a suitable opponent to against one another in a tournament. This is largely due to the manual matchmaking method that only randomly matches one team with another. Consequently, it is crucial to ensure a balanced tournament bracket where eventual winners and losers not facing one another in the very first round. This study proposes an intelligent matchmaking using Particle Swarm Optimization (PSO) and tournament management system for paintball organizers. PSO is a swarm intelligence algorithm that optimizes problems by gradually improving its current solutions, therefore countenancing the tournament bracket to be continually improved until the best is produced. Indirectly, through the development of the system, it is consider as an intelligence business idea since it able to save time and enhance the company productivity. This algorithm has been tested using 3 size of population; 100, 1000 and 10,000. As a result, the speed of convergence is consistent and has not been affected through big population.N. N. S. Abdul Rahman, N.M. Saad, A. R. Abdullah, M. R. M. Hassan, M. S. S. M. Basir, N. S. M. Noor 1,2,4,6Faculty of Electronic and Computer Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 2,3Center for Robotics and Industrial Automation, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, Malaysia 3,5Faculty of Electrical Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, MalaysiaLight rail transit (LRT), or fast tram is urban public transport using rolling stock similar to a tramway, but operating at a higher capacity, and often on an exclusive right-of-way. Indonesia as one of developing countries has been developed the LRT in two cities of Indonesia, Palembang and Jakarta. There are opinions toward the development of LRT, negative and positive opinions. To reveal the level of LRT development acceptance, this research uses machine learning approach to analyze the data which is gathered through social media. By conducting this paper, the data is modeled and classified in order to analyze the social sentiment towards the LRT development.Mohamad, S., Nasir, F.M., Sunar, M.S., Isa, K., Hanifa, R.M., Shah, S.M., Ribuan, M.N., Ahmad, A. 1,4,6,7,8Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia, Johor, Malaysia 1,2,3UTM-IRDA Digital Media Centre, Media and Game Innovation Centre of Excellence, Universiti Teknologi Malaysia, Johor, Malaysia 1,2,3Faculty of Computing, Universiti Teknologi Malaysia, Johor, Malaysia 5Centre for Diploma Studies, Universiti Tun Hussein Onn Malaysia, Johor, Malaysia 6Research Centre for Applied Electromagnetics, Universiti Tun Hussein Onn Malaysia, Johor, MalaysiaReceived Jan 31, 2018 Revised Apr 21, 2018 Accepted Apr 30, 2018 Bluetooth is an emerging mobile ad-hoc network that accredits wireless communication to connect various short range devices. A single hop network called piconet is the basic communication topology of bluetooth which allows only eight active devices for communication among them seven are active slaves controlled by one master. Multiple piconets are interconnected through a common node, known as Relay, to form a massive network called as Scatternet. It is obvious that the performance of Scatternet scheduling is highly dependent and directly proportionate with the performance of the Relay node. In contrary, by reducing the number of Relays, it may lead to poor performance, since every Relay has to perform and support several piconet connections. The primary focus of this study is to observe the performance metrics that affects the inter-piconet scheduling since the Relay node’s role is like switch between multiple piconets. In this paper, we address and analyze the performance issues to be taken into consideration for efficient data flow in Scatternet based on Relay node.