• Title, Summary, Keyword: Load shedding

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A Study on Multi Level Load Shedding Control Scheme Strategy for Stabilization of the Korean Power System (국내 전력계통 안정화를 위한 다단계 부하차단 제어전략 수립에 관한 연구)

  • Lee, Yun-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.65 no.4
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    • pp.255-261
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    • 2016
  • Korean Power System are operating a load shedding system to prevent voltage instability phenomenon caused by severe line contingencies. In order to apply the load shedding scheme should be selected a location, amount, delay time. Current load shedding system is load shedding amount that has been calculated in the steady-state analysis to load shed the total amount in first level, load shedding amount calculated in advance, it is possible to perform an unnecessary load shedding. In this paper, set a multi-level load shedding control strategy step-by-step selection of load shedding amount for the prevention of excessive load shedding. In addition, through a voltage resilience analysis of the power system by applying motor load ratio and sensitivity parameter to selection the multi level load shedding ratio and delay time. For this reason, to take advantage of the limit data of interchange power, by utilizing interface power flow data to set a multi-level load shedding control strategy for the stabilization of the Korean Power System.

A Study on the Application of Under Voltage Load Shedding Scheme in Line Contingency considering Motor Load (모터부하를 고려한 상정사고 발생 시 저전압 부하차단 적용 방안에 대한 연구)

  • Lee, Yun-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.66 no.1
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    • pp.21-26
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    • 2017
  • Failure of high-voltage transmission line, which is responsible for large-scale power transmission, can be reason for system voltage instability. There are many methods to prevent voltage instability like adjustment of equipment, the generator voltage setting, and load shedding. Among them, the load shedding, have a problem of economic loss and cascading effect to power system. Therefore, the execution of load shedding, amount and timing is very important. Conventionally, the load shedding setting is decided by the preformed simulation. Now, it is possible to monitor the power system in real time by the appearance of PMU(Phasor Measurement Unit). By this reason, some of research is performed about decentralized load shedding. The characteristics of the load can impact to amount and timing of decentralized load shedding. Especially, it is necessary to consider the influence of the induction motor loads. This paper review recent topic about under voltage load shedding and compare with decentralized load shedding scheme with conventional load shedding scheme. And simulations show the effectiveness of proposed method in resolving the delayed voltage recovery in the Korean Power System.

An Adaptive Undervoltage Load Shedding Against Voltage Collapse Based Power Transfer Stability Index

  • Nizam, Muhammad;Mohamed, Azah;Hussain, Aini
    • Journal of Electrical Engineering and Technology
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    • v.2 no.4
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    • pp.420-427
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    • 2007
  • This paper highlights the comparison of a proposed methods named adaptive undervoltage load shedding based PTSI techniques for undervoltage load shedding and two previous methods named Fixed Shed Fixed Delay (FSFD) and Variable Shed Variable Delay (VSVD) for avoiding voltage collapse. There are three main area considerations in load shedding schemes as the amount of load to be shed, the timing of load shedding event, and the location where load shed is to be shed. The proposed method, named as adaptive UVLS based PTSI seem to be most appropriate among the uncoordinated schemes. From the simulation result can be shown the Adaptive UVLS based PTSI give faster response, accurate and very sensitive control for the UVLS control technique. This technique is effectively when calculating the amount to be shed. Therefore, it is possible to bring the voltage to the threshold value in one step. Thus, the adaptive load shedding can effectively reduce the computational time for control strategy.

Talmudic Approach to Load Shedding of Islanded Microgrid Operation Based on Multiagent System

  • Kim, Hak-Man;Kinoshita, Tetsuo;Lim, Yu-Jin
    • Journal of Electrical Engineering and Technology
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    • v.6 no.2
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    • pp.284-292
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    • 2011
  • This paper presents a load-shedding scheme using the Talmud rule in islanded microgrid operation based on a multiagent system. Load shedding is an intentional load reduction to meet a power balance between supply and demand when supply shortages occur. The Talmud rule originating from the Talmud literature has been used in bankruptcy problems of finance, economics, and communications. This paper approaches the load-shedding problem as a bankruptcy problem. A load-shedding scheme is mathematically expressed based on the Talmud rule. For experiment of this approach, a multiagent system is constructed to operate test islanded microgrids autonomously. The suggested load-shedding scheme is tested on the test islanded microgrids based on the multiagent system. Results of the tests are discussed.

LOAD SHEDDING SIMULATION FOR MAINTAINING FREQUENCY STABILITY-GAS SEPARATION PLANT CASE (주파수 안정도 유지를 위한 부하차단 시뮬레이션-가스분리플랜트 사례)

  • Kim, Bong-Hee
    • Proceedings of the KIEE Conference
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    • pp.72_73
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    • 2009
  • The industrial power system has the radial plant distribution system and domestic generators to supply the essential loads. When the system is isolated from the utility tie line, the system frequency drops resulting in the trip of generators. The load shedding scheme shall be properly designed to secure the essential load. In this paper two kinds of load shedding schemes, those are, the Fast Act Load Shedding(FALS) and Under Frequency Load Shedding(UFLS) are simulated and compared taking an example of petrochemical gas separation plant.

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Utilizing Under Voltage Load Shedding Strategy to Prevent Delayed Voltage Recovery Problem in Korean Power System

  • Lee, Yun-Hwan;Oh, Seung-Chan;Lee, Hwan-Ik;Park, Sang-Geon;Lee, Byong-Jun
    • Journal of Electrical Engineering and Technology
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    • v.13 no.1
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    • pp.60-67
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    • 2018
  • The presence of induction motor loads in a power system may cause the phenomenon of delayed voltage recovery after the occurrence of a severe fault. A high proportion of induction motor loads in the power system can be a significant influence on the voltage stability of the system. This problem referred to as FIDVR(Fault Induced Delayed Voltage Recovery) is commonly caused by stall of small HVAC unit(Heating, Ventilation, and Air Conditioner) after transmission or distribution system failure. This delayed voltage recovery arises from the dynamic characteristics associated with the kinetic energy of the induction motor load. This paper proposes the UVLS (Under Voltage Load Shedding) control strategy for dealing with FIDVR. UVLS based schemes prevent voltage instability by shedding the load and can help avoid major economic losses due to wide-ranging cascading outages. This paper review recent topic about under voltage load shedding and compare decentralized load shedding scheme with conventional load shedding scheme. The load shedding strategy is applied to an actual system in order to verify the proposed FIDVR mitigation solution. Simulations demonstrate the effectiveness of the proposed method in resolving the problem of delayed voltage recovery in the Korean Power System.

Load shedding case study of the refinery plant power system considering dynamic characteristic (정유공장 전력계통 동특성을 고려한 부하차단 적용 사례연구)

  • Lee, Kang-Wan;Lim, Joo-Il;Kim, Hyung-Tae
    • Proceedings of the KIEE Conference
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    • pp.61-65
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    • 2000
  • This paper presents the load shedding case studies and recommendations of load shedding scheme For improving the reliability to suit the requirements of LG-Caltex refinery plant power sγstem. It is recommended for LG-Caltex to decrease the total generation for the economic dispatch. When the LG-Caltex refinery is isolated from KEPCO utility system, the proper load shedding scheme should be implemented since total generation in LG-Caltex refinery plant is less than the load demand. According to the studies carried out the logic-based load shedding is recommended as the main protection scheme, with the combination of the under-frequency relay load shedding.

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A Study on Decentralized under Voltage Load Shedding Scheme for Preventing Wide-area Black Out (광역정전 예방을 위한 분산형 부하 제어 방안에 대한 연구)

  • Lee, Yun-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.1
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    • pp.1-6
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    • 2014
  • An electric power system sometimes fails because of disturbances that occur unexpectedly, such as the uncontrolled loss of load that developed from cascading blackout. Which make stability through a little of under voltage load shedding should work. The development of phasor measurement unit(PMU) makes network supervision possible. The information obtained from PMU is synchronized by global positioning system(GPS). There are many real-time algorithms which are monitoring the voltage stability. This paper presents the study on the VILS(Voltage Instability Load Shedding) using PMU data. This algorithm computes Voltage Stability Margin Index(VSMI) continuously to track the voltage stability margin at local bus level. The VSMI is expressed as active and reactive power. The VSMI is used as an criterion for load shedding. In order to examine the algorithm is effective, applied to KEPCO system.

Multi-level UnderVoltage Load Shedding Scheme Considering Rate of Change of Voltage for Voltage Stability (전압 변동률을 고려한 수도권 전압 안정화 다단계 부하차단 적용 방안)

  • Lee, Yun-Hwan;Kim, Tae-Gyun;Kim, Ji-Hun;Lee, Byong-Jun;Kang, Bu-Il;Cho, Jong-Man
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.12
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    • pp.2335-2341
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    • 2009
  • High technique growth of modem times and high industrial facility in consequence of buildings demand for electric power of an extensive scale with stability supply and maintenance of high quality. But, power system always have risk of network contingency. When power system break out disturbance, it circumstantially happen like uncontrolled loss of load developing from of cascading. Severely which would be raised wide area blackout, plan to prevent, which make stability through a little of load shedding and multi-level UnderVoltageLoadShdding should work. This paper presents target, sensitivity of bus voltage have choose appropriating load shedding location and load shedding decision making logic with considering rate of change of voltage have studied multi-level under voltage load shedding scheme. Calculation of rate of change of voltage applied method of least square. As a result, we are studied an dynamic analysis of 2008 summer peak data. We have been known that network analysis is a little development and developing UnderVoltageLoadShedding scheme.

A Study on the Determination of Minimum Local Load Shedding Considering the Regional DLC Potentials (지역별 직접부하제어 잠재량을 고려한 부하차단 확보량 결정에 관한 연구)

  • Shim, K.B.;Kim, J.H.;Hwang, S.W.;Lee, C.H.;Cho, I.S.
    • Proceedings of the KIEE Conference
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    • pp.407-409
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    • 2002
  • This paper proposes a process using the load shedding scenario method that determines the minimum local load shedding quantity considering the local DLC(Direct Load Control) potentials. So this method is applied to Kyung-In area and determined the load shedding of this area with comparison to its DLC potentials.

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