• Title/Summary/Keyword: Optimal Voltage

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A study on the Optimal Operation of Step Voltage Regulator(SVR) in the Distribution Feeders(3) (고압배전선로의 선로전압조정장치(SVR)의 최적운용에 관한 연구(3))

  • Lee, Eun-Mi;Rho, Dae-Seok;Park, Chang-Ho
    • Proceedings of the KIEE Conference
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    • 2003.11a
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    • pp.97-99
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    • 2003
  • This paper deals with optimal voltage regulation methods of line voltage regulator(SVR : Step Voltage Regulator) in power distribution systems. In order to deliver suitable voltages to as many customers as possible, the optimal sending voltage of SVR should be decided by the effective operation of voltage regulators at the distribution feeders and substations. In this paper, a new voltage regulation method based on the existing method is presented and an optimal coordination method of multiple voltage regulators is extended. The results from a case study show that the proposed methods can be a practical tool for the voltage regulation in distribution systems.

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A Study on the Optimal Voltage for MPPT Obtained by only Surface's Temperature of Solar Cell (태양전지 온도 센싱만을 통한 태양광 발전시스템의 최적 운전전압에 관한 연구)

  • Minwon Park;In-Keun Yi
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.4
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    • pp.269-275
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    • 2004
  • Photovoltaic(PV) system has been studied and watched with keen interest due to a clean and renewable power source. But, the output power of PV system is not only unstable but uncontrollable, because the maximum power point tracking (MPPT) of PV system is still hard with the tracking failure under the sudden fluctuation of irradiance. Authors suggest that the optimal voltage for MPPT be obtained by only solar cell temperature. Having an eye on that the optimal voltage point of solar cell is in proportion to its panel temperature, with operating the power converter whose operating point keeps its input voltage to the optimal voltage imagined by the surface's temperature of PV panel, the maximum power point becomes tenderly possible to be tracked. In order to confirm the availability of the proposed control scheme. And both control methods are simulated not only on the various angle of sampling time of switching control, but also with the real field weather condition. As the results of that, the conversion efficiency between PV panel and converter of the proposed control scheme was much better than that of the power comparison MPPT control, and what is better, the output voltage of PV panel was extremely in stable when the optimal voltage for MPPT is obtained by only solar cell temperature.

A Study on the Optimal Introduction of Step Voltage Regulator(SVR) in Distribution Feeders (고압배전선로용 선로전압조정장치(SVR)의 최적 도입방안에 관한 연구)

  • Lee Eun-Mi;Kim Mi-Young;Rho Dae-Seok;Sohn Sang-wook;Kim Jae-Eon;Park Chang-Ho
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.53 no.11
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    • pp.610-618
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    • 2004
  • With the development of industry and the improvement of living standards, better quality in power electric service is required more than ever before. Under these circumstances, to deliver reasonable voltage regulation methods in distribution systems need to be developed. So, This paper deals with optimal introduction of the line voltage regulator (SVR : Step Voltage Regulator) in power distribution systems. First, This paper investigates characteristics of SVR and performs economic evaluation of SVR's introduction by using Present Worth Method. This paper, also suggests proper location and optimal voltage regulation algorithm. In order to deliver suitable voltages to as many customers as possible, the optimal sending voltage of SVR should be decided by the effective operation of voltage regulators at the distribution feeders. The simulation results using a model distribution system and real distribution systems show that the proposed methods can be a practical tool for the voltage regulation in distribution systems.

An Operation Method of Many UPFC's for Maintaining the Optimal Voltage Profile (계통 최적전압 상태 유지를 위한 다기 UPFC 운용방법)

  • Kim, Tae-Hyun;Moon, Seung-Il;Park, Jong-Keun
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.49 no.11
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    • pp.531-535
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    • 2000
  • A method to compute the reactive powers of the added buses by the decoupled UPFC model for the optimal voltage profile is presented, by which the voltage magnitudes of PQ buses can get closer to the reference value(usually one p.u.). The performance index for assessing how much the voltage magnitude is closer to the reference value is defined as the squared sum of the present voltage minus the reference voltage multiplied by the weighting number associated with the relative importance of the buses. Numerical example in a 10-unit 39-bus power system with 2 UPFC's shows that the performance index can be very much reduced by operating many UPFC's with the reactive powers for the optimal voltage profile proposed in this paper.

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Voltage Stability Constrained Optimal Power Flow based on Successive Linear Programming (전압안정도를 고려한 연속선형계획법 기반 최적조류계산)

  • Bae, Seung-Chul;Shin, Yong-Son;Lee, Byong-Jun
    • Proceedings of the KIEE Conference
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    • 2003.11a
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    • pp.220-223
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    • 2003
  • This paper presents VSCOPF(Votage Stability Constrained Optimal Power Flow) algorithm based on SLP(Successive Linear Programming) to interpret the large scale system. Voltage stability index used to this paper is L index to be presented by function form. The objective function consists of load shedding cost minimization. Voltage stability indicator constraint was incorporated in traditional OPF formulation. as well as the objective function and constraints are linearlized and the optimal problem is performed by SLP(Successive Linear Programming). In this paper, the effect of voltage stability limit constraint is showed in the optimal load curtailment problems. As a result, an optimal solution is calculated to minimize load shedding cost guaranteeing voltage security level. Numerical examples using IEEE 39-bus system is also presented to illustrate the capabilities of the proposed formulation.

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Optimal Placement of Distributed Generation Units Considering Voltage Sags (순간전압강하를 고려한 분산전원 최적위치 선정)

  • Song, Young-Won;Lee, Kyebyung;Park, Chang-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.11
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    • pp.1505-1510
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    • 2013
  • This paper presents a method for determining the optimal placement of distributed generation units considering voltage sags. In general, the existing methods for distributed generation placement do not consider power quality problems such as voltage sags. In this paper, a novel method based on both genetic algorithm and voltage sag assessment is proposed for determining the placement of distributed generation unit. In the proposed method, the optimal placement is determined to minimize voltage sag effects and system losses.

Method to Select Optimal Device for Mitigating Voltage Sag Based on Voltage Sag Assessment (순간전압강하 평가에 기반한 최적 보상기기 선정 방법)

  • Lee, Kyebyung;Han, Jong-Hoon;Jang, Gilsoo;Park, Chang-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.1
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    • pp.29-34
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    • 2015
  • This paper presents a method to select optimal device for mitigating voltage sags. The method is based on economic evaluation and voltage sag assessment involving sag duration as well as magnitude. The economic evaluation is performed by using the operation cost and economic benefit of the mitigation devices. The optimal device can be determined from the values of NPV (net present value) which is widely accepted in cost-benefit analysis. The proposed method can help sensitive customers to select optimal mitigation device. In this paper, the case study considering two sensitive customers was performed by using the proposed method.

A Study on the Optimal Voltage Regulation in Distribution Systems with Dispersed Generation Systems (분산형전원이 도입된 배전계통의 최적전압조정 방안에 관한 연구)

  • Kim Mi-Young;Oh Yong-Taek;An Jae-Yun;Kim Jae-Eon;Kim Eung_Sang;Rho Dae-Seok
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.54 no.5
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    • pp.251-258
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    • 2005
  • Recently, the domestic and foreign power trends are the supply of high quality power and environment conservation technology based on the new energies development. So, the dispersed generation systems, such as photovoltaic, fuel cell, and battery are to be introduced in distribution systems. According to the situation change, power of high Quality and reliability are required in distribution systems with dispersed generation. Up to now, the voltage in distribution systems are regulated by ULTC of substation and pole transformer of primary feeders. These days, Step Voltage Regulator(SVR) is getting established at distribution feeders to regulate effectively voltage of primary ffeders that voltage drop exceeds $5\%$. But, because SVR is operated independently with ULTC of substation, SVR can not take play to its full effectivity. Under these circumstances, in order to deliver suitable voltages to as many customers as possible, new optimal voltage regulation algorithms are required in distribution system. So, this paper presents optimal voltage regulation algorithm to regulate voltage effectively for ULTC and SVR in distribution systems with dispersed generation systems.

Optimal Voltage Regulation Method for Distribution Systems with Distributed Generation Systems Using the Artificial Neural Networks

  • Kim, Byeong-Gi;Rho, Dae-Seok
    • Journal of Electrical Engineering and Technology
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    • v.8 no.4
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    • pp.712-718
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    • 2013
  • With the development of industry and the improvement of living standards, better quality in power electric service is required more than ever before. This paper deals with the optimal algorithms for voltage regulation in the case where Distributed Storage and Generation (DSG) systems are operated in distribution systems. It is very difficult to handle the interconnection issues for proper voltage managements, because the randomness of the load variations and the irregular operation of DSG should be considered. This paper proposes the optimal on-line real time voltage regulation methods in power distribution systems interconnected with the DSG systems. In order to deliver suitable voltage to as many customers as possible, the optimal sending voltage should be decided by the effective voltage regulation method by using artificial neural networks to consider the rapid load variation and random operation characteristics of DSG systems. The simulation results from a case study show that the proposed method can be a practical tool for the voltage regulation in distribution systems including many DSG systems.

A Study on the Optimal Routing Technique for the Improvement of Voltage Stability in Radial Power System (방사상 전력계통의 전압안정도 향상을 위한 최적 라우팅 기법에 관한 연구)

  • Kim, Byung-Seop;Shin, Joong-Rin;Park, Jong-Bae
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.11
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    • pp.568-576
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    • 2002
  • This paper presents a new algorithm for the enhancement of voltage stability by optimal routing (OR) technique. A new voltage stability index (VSI) for optimal routing is also proposed by using theories of critical transmission path based on voltage phasor approach and equivalent impedance method. Furthermore, the proposed algorithm automatically detect the critical transmission path to critical transmission path to critical load which are faced to voltage collapse due to additional real or reactive loading. We also adopt a improved branch exchange (IBE) algorithm based on a tie branch power (TBP) flow equation to apply the OR technique. The proposed IBE algorithm for the VSI maximizing can effectively search the optimal topological structures of distribution feeders by changing the open/closed states of the sectionalizing and tie switches. The proposed algorithm has been evaluated with the practical IEEE 32, 69 bus test systems and KEPCO 148 bus test system to show favorable performance.