• Title/Summary/Keyword: power penalty

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A Study on Effective Enhancement of Load Power Factor Using the Load Power Factor Sensitivity of Generation Cost

  • Lee Byung Ha;Kim Jung-Hoon
    • KIEE International Transactions on Power Engineering
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    • v.5A no.3
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    • pp.252-259
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    • 2005
  • Various problems such as increase of power loss and voltage instability may often occur in the case of low load power factor. The demand of reactive power increases continuously with the growth of active power and restructuring of electric power companies makes the comprehensive management of reactive power a troublesome problem, so that the systematic control of load power factor is required. In this paper, the load power factor sensitivity of generation cost is derived and it is used for effectively determining the locations of reactive power compensation devices and for enhancing the load power factor appropriately. In addition, voltage variation penalty cost is introduced and integrated costs including voltage variation penalty cost are used for determining the value of load power factor from the point of view of economic investment and voltage regulation. It is shown through application to a large-scale power system that the load power factor can be enhanced effectively using the load power factor sensitivity and the integrated cost.

Generator Penalty Factor Calculation including Slack Bus by Reference Angle Re-Specification (위상각 기준모선의 이동에 의한 Slack 모선을 포함한 모든 발전기의 Penalty 계수 계산방법)

  • Lee, Sang-Joong;Kim, Kern-Joong
    • Proceedings of the KIEE Conference
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    • 2000.07a
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    • pp.49-51
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    • 2000
  • ln this paper, a method by which penalty factors of all generators including slack bus can be directly derived is presented. With a simple re-assignment of angle reference bus to a bus where no generation exists, penalty factors for slack bus is obtained without any physical assumption. While previous Jacobian-based techniques for generator penalty factor calculation have been derived with basis upon reference bus, proposed method are not dependent on reference bus and calculated penalty factors can be substituted directly into the general ELD equation to compute the economic dispatch. Equations for system loss sensitivity, penalty factors and optimal generation allocation are solved simultaneously in normal power flow computation.

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A Study on the Effective Enhancement of the Load Power Factor Using the Load Power Factor Sensitivity of Generation Cost (부하역률 감도기법 적용에 의한 효율적인 부하역률 개선에 관한 연구)

  • Lee Byung Ha;Kim Jung-Hoon
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.54 no.1
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    • pp.18-24
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    • 2005
  • Various problems such as the increase of the power loss and the voltage instability may often occur in the case of low load power factor. The demand of reactive power increases continuously with the growth of active power and the restructuring of electric power companies makes the comprehensive management of reactive power a troublesome problem, so that the systematic control of load power factor is required. In this paper, the load power factor sensitivity of the generation cost is derived and it is used for determining the locations of reactive power compensation devices effectively and for enhancing the load power factor appropriately. In addition, the voltage variation penalty cost is introduced and the integrated costs including the voltage variation penalty cost are used for determining the value of the load power factor from the point of view of the economic investment and voltage regulation. It is shown through the application to a large-scale power system that the load power factor can be enhanced effectively and appropriately using the load power factor sensitivity and integrated costs.

Power Performance of Instruction Pre-Fetch Unit (명령어 선 인출기의 전력 성능)

  • 송영규;오형철
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.365-368
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    • 1999
  • In this paper, we investigate the effect of adopting branch-penalty compensation schemes on the power performance of TLBs(Translation Look-aside Buffers) and instruction caches. We found that the double-buffer branch-penalty compensation scheme can reduce the power consumption of the TLBs and the instruction caches considered by up to 14-21.3%. The power consumption is estimated through simulation at the architectural level, using the Kamble/Ghose method

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An Improved Analytic Model for Power System Fault Diagnosis and its Optimal Solution Calculation

  • Wang, Shoupeng;Zhao, Dongmei
    • Journal of Electrical Engineering and Technology
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    • v.13 no.1
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    • pp.89-96
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    • 2018
  • When a fault occurs in a power system, the existing analytic models for the power system fault diagnosis could generate multiple solutions under the condition of one or more protective relays (PRs) and/or circuit breakers (CBs) malfunctioning, and/or an alarm or alarms of these PRs and/or CBs failing. Therefore, this paper presents an improved analytic model addressing the above problem. It takes into account the interaction between the uncertainty involved with PR operation and CB tripping and the uncertainty of the alarm reception, which makes the analytic model more reasonable. In addition, the existing analytic models apply the penalty function method to deal with constraints, which is influenced by the artificial setting of the penalty factor. In order to avoid the penalty factor's effects, this paper transforms constraints into an objective function, and then puts forward an improved immune clonal multi-objective optimization algorithm to solve the optimal solution. Finally, the cases of the power system fault diagnosis are served for demonstrating the feasibility and efficiency of the proposed model and method.

Study on BESS Charging and Discharging Scheduling Using Particle Swarm Optimization (입자 군집 최적화를 이용한 전지전력저장시스템의 충·방전 운전계획에 관한 연구)

  • Park, Hyang-A;Kim, Seul-Ki;Kim, Eung-Sang;Yu, Jung-Won;Kim, Sung-Shin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.4
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    • pp.547-554
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    • 2016
  • Analyze the customer daily load patterns, be used to determine the optimal charging and discharging schedule which can minimize the electrical charges through the battery energy storage system(BESS) installed in consumers is an object of this paper. BESS, which analyzes the load characteristics of customer and reduce the peak load, is essential for optimal charging and discharging scheduling to save electricity charges. This thesis proposes optimal charging and discharging scheduling method, using particle swarm optimization (PSO) and penalty function method, of BESS for reducing energy charge. Since PSO is a global optimization algorithm, best charging and discharging scheduling can be found effectively. In addition, penalty function method was combined with PSO in order to handle many constraint conditions. After analysing the load patterns of target BESS, PSO based on penalty function method was applied to get optimal charging and discharging schedule.

Analysis on power penalty due to timing jitters when considering intersymbol interference in the receivers on intensity modulation/direct detection optical communication systems (강도변조/직접검파 광통신 수신기에서 심벌간 간섭을 고려할 경우 타이밍 지터에 의한 잔력 페널티 해석)

  • 은수정;심요안;김부균
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.4
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    • pp.1077-1088
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    • 1996
  • In this paper, we propose a new method to analyze the performance degradation by timing jitters in the receivers of intensity modulation/direct detection digital optical communication systems where pulse-shaping filters are used to minimize intersymbol interference. The results obtained from the proposed analytical method show that conventional analytical methods underestimate the influence of timing jitters on the receiver performance. Using the proposed anlaytical method, we derive an analytic equation for approximated power penalty due to timing itters and obtain an exact power penalty by numerical analyses. Assuming Gaussian or uniform probability density function for timing jitters, we also show that assumption of Gaussian distribution for timing jitters yields more performance degration than that of uniform distribution.

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Design of a Fixed-Structure H$_{\infty}$ Power System Stabilizer (고정 구조를 가지는$H_\infty$ 전력계통 안정화 장치 설계)

  • Kim Seog-Joo;Lee Jong-Moo;Kwon Soonman;Moon Young-Hyun
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.53 no.12
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    • pp.655-660
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    • 2004
  • This paper deals with the design of a fixed-structure $H_\infty$ power system stabilizer (PSS) by using an iterative linear matrix inequality (LMI) method. The fixed-structure $H_\infty$ controller is represented in terms of LMIs with a rank condition. To solve the non-convex rank-constrained LMI problem, a linear penalty function is incorporated into the objective function so that minimizing the penalized objective function subject to LMIs amounts to a convex optimization problem. With an increasing sequence of the penalty parameter, the solution of the penalized optimization problem moves towards the feasible region of the original non-convex problem. The proposed algorithm is, therefore, convergent. Numerical experiments show the practical applicability of the proposed algorithm.

A New Calculation of Generator Penality Factors through transposition of System Angle Reference (위상각기준의 이동을 통한 새로운 패널티 계수의 계산방법)

  • Lee, Sang-Joong
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.50 no.1
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    • pp.1-5
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    • 2001
  • In this paper, a new method for calculating the penalty factors of all generators including the slack bus is presented. A simple transposition of the angle reference, from the conventional slack bus to another bus where no generation exists, enables the derivation of the loss sensitivity of the slack bus. Penalty factors are obtained without any physical assumption through a simple substitution of the bus loss sensitivities. Penalty factors calculated by proposed method are not dependent on reference bus and can also be directly substituted into the general ELD equation for computing the optimal dispatch. Equations for loss sensitivities, Penalty factors and ELD are calculated simultaneously in normal power flow computation. A case study on a test system has proved the effectiveness of the proposed' angle reference transposition' method.

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