A Review on Equipment Protection and System Protection Relay in Power System

Power system equipment is configured and connected together with multiple voltage levels in existing electrical power system. There are varieties of electrical equipment obtainable in the power system predominantly from generation side up to the distribution side. Consequently, appropriate protections must be apt to prevent inessential disturbances that lead to voltage instability, voltage collapse and sooner a total blackout took place in the power system. The understanding of each component on the system protection is critical. This is due to any abnormal condition and failure can be analyzed and solved effectively due to the rapid changing and development on the power system network. Therefore, the enhancement of power quality can be achieved by sheltering the equipment with protection relay in power system. Moreover, the design of a systematic network is crucial for the system protection itself. Several types of protective equipment and protection techniques are taken into consideration in this paper. Hence, the existing accessible types and methods of system protection in the power system network are reviewed

Reliable Power System Operation Plan: Steady State Contingency Analysis

Steady state contingency analysis focuses at the evaluation of the risk certain contingency possibly causes to an electrical network. This analysis is used to review the outage of elements such as transmission lines, transformers and generators, and investigation of the resulting effects on line power flows and bus voltages in Sabah, Malaysia grid transmission system. This is an extremely significant duty for network operators since network stability issues become essentially critical in electricity deregulation. In this paper, the analysis is performed to ensure the system meets grid code standards during normal operations and variety of contingencies condition. Therefore, this paper intended to put forward issues and recommendations towards attaining a steady power system operation plan. Steady state contingency analysis is to calculate power flows in outage states in which one or more system components are out of service. A transmission system must satisfy security criteria in both normal and outage states. This paper presented the steady state contingency analysis for the period of year 2015. The contingency analysis are performed by using the Siemens PTI software, Power System Simulator for Engineering (PSS/E)

An Overview of Out-Of-Step Protection in Power Systems

Power system is subjected to an extensive variety of little or bigger disturbance to the system during the operation. The power system that designed as one of the main requirement is to survive from the larger type of disturbances like faults. The power swing in certain system is the variation in three phase power flow in the power system. This paper mainly discussed the power swing and distance relay and the effect of the power swing on the distance relay and demonstrate about the basic power system stability and power swing phenomena. Moreover, out of step protection and detection applications are revised as well. At the end, the paper also demonstrated the past study of out of step application of TNB 275 KV network

Extend the debt as it is not deeply out-of-the-money

In this paper, we modify the extendible debts model proposed in Longstaff (1990) to help relieve the moral hazard problem induced in the original model. In Longstaff¡¦s model, extending the maturity of the defaulted debts gives the borrower an incentive to default even if the borrower is insolvent. In this paper, we argue that the debt should not be extended if it is defaulted severely. We have shown that the extendible debt valuation can be obtained by the compound option pricing besides the PDE approach. We also have derived the fair interest rate of the extendible debts in this paper.

An Empirical Study on the Information Formality Motivation, Social Influence, and Goal Commitment of Knowledge Workers

A knowledge worker\u27s goal commitment is critical to the success of system implementation in the organization. This paper investigates an individual\u27s information formality motivation and social influence as important determinants in developing goal commitment in the system implementation based on the social psychology and information management literature. An empirical test of the proposed model was conducted in the field test (n = 148). PLS was used to analyze the model and supported the validity of the results. Social influence and information formality influence knowledge worker\u27s goal commitment (R2 = 0.36) as expected. Social influence has a higher effect on goal commitment than information formality motivation. The results of this study will help us understand the antecedents of goal commitment in the system implementation based on the social influence theory and personal information management model. The paper includes implications for the designers and information system (IS) managers to effectively understand knowledge worker\u27s goal commitment in the organization

Pseudo-solidification of dredged marine soils with cement - fly ash for reuse in coastal development

The dislodged and removed sediments from the seabed, termed dredged marine soils, are generally classified as a waste material requiring special disposal procedures. This is due to the potential contamination risks of transporting and disposing the dredged soils, and the fact that the material is of poor engineering quality, unsuitable for usage as a conventional good soil in construction. Also, taking into account the incurred costs and risk exposure in transferring the material to the dump site, whether on land or offshore, it is intuitive to examine the possibilities of reusing the dredged soils, especially in coastal development where the transportation route would be of shorter distance between the dredged site and the construction location. Pseudo-solidification of soils is not a novel idea though, where hydraulic binders are injected and mixed with soils to improve the inherent engineering properties for better load bearing capacity. It is commonly used on land in areas with vast and deep deposits of soft, weak soils. However, to implement the technique on the displaced then replaced dredged soil would require careful study, as the material is far more poorly than their land counterparts, and that the deployment of equipment and workforce in a coastal environment is understandably more challenging. The paper illustrates the laboratory investigation of the improved engineering performance of dredged marine soil sample with cement and fly ash blend. Some key findings include optimum dosage of cement and fly ash mix to produce up to 30 times of small strain stiffness improvement, pre-yield settlement reduction of the treated soil unaffected by prolonged curing period, and damage of the cementitious bonds formed by the rather small dosage of admixtures in the soil post-yield. In short, the test results show a promising reuse potential of the otherwise discarded dredged marine soils

An overview of out-of-step protection in power systems

Power system is subjected to an extensive variety of little or bigger disturbance to the system during the operation. The power system that designed as one of the main requirement is to survive from the larger type of disturbances like faults. The power swing in certain system is the variation in three phase power flow in the power system. This paper mainly discussed the power swing and distance relay and the effect of the power swing on the distance relay and demonstrate about the basic power system stability and power swing phenomena. Moreover, out of step protection and detection applications are revised as well. At the end, the paper also demonstrated the past study of out of step application of TNB 275 KV network

Anticipating Exponential Processes and Stochastic Differential Equations

Exponential processes in the Ito theory of stochastic integration can be viewed in three aspects: multiplicative renormalization, martingales, and stochastic differential equations. In this paper we initiate the study of anticipating exponential processes from these aspects viewpoints. The analogue of martingale property for anticipating stochastic integrals is the near-martingale property. We use examples to illustrate essential ideas and techniques in dealing with anticipating exponential processes and stochastic differential equations. The situation is very different from the Ito theory

State Transportation Improvement Program for Federal Fiscal Years 2011-2014

OBJECTIVES:To develop and validate a Taiwanese version of the Health Enhancement Lifestyle Profile (HELP-T) for community-dwelling older Taiwanese adults (≥ 55 years). METHODS:The original Health Enhancement Lifestyle Profile (HELP) is a 56-item self-report questionnaire measuring various aspects of health-related lifestyles in older adults. The standard cultural-adaptation procedure was used for questionnaire translation and modification. A field test was conducted for culturally specific item selection, rating-scale analysis, and psychometric validation of the HELP-T in a sample of 274 community-dwelling older adults via classical test theory. RESULTS:The 59-item HELP-T is culturally adapted from the original 56-item HELP. The original 6-point rating scale was modified to a 3-point scale for easy use by Taiwanese older adults. The HELP-T had good internal consistency (Cronbach's alpha = 0.82). The test-retest reliability for the total score was high (0.92), and moderate to high (range: 0.57-0.92) for subscales. The construct validity was supported by the significant correlations between each subscale and the total score (Spearman's rho = 0.41-0.67, p < 0.0001) and by the ability of the scores to significantly discriminate between participants with different levels of self-rated health (p = 0.0001). CONCLUSIONS:The HELP-T is a suitable clinical tool for assessing and monitoring lifestyle risk factors, establishing client-centered lifestyle intervention goals, and determining the outcomes of lifestyle interventions