• Title/Summary/Keyword: Voltage Collapse Point

Search Result 38, Processing Time 0.022 seconds

DIRECT COMPUTATION OF MARGINAL OPERATING CONDITIONS FOR VOLTAGE COLLAPSE

  • Lee, Kyung-Jae;Jung, Tay-Ho
    • Proceedings of the KIEE Conference
    • /
    • 1989.07a
    • /
    • pp.195-201
    • /
    • 1989
  • Voltage collapse is a serious concern to the electirc utility industry. It is common to associate steady-state stability with the ability of the transmission system to transport real power and to associate voltage collapse with the inability to provide reactive power at the necessary locations within the system. An algorithm to directly calculate the critical point of system voltage collapse was presented by the authors. The method (based on the ordinary power flow equations and explicit requirement of singularity of the Jacobian matrix) is basically one degree of freedom with proper load distribution factors. This paper suggests a modified algorithm to increase the degree of freedom, introducing the nonlinear programming technique. The objective function is a distance measure between the present operating point and the closest voltage collapse point. Knowledge of the distance and the most vulnarable bus from the voltage collapse point of view may be used as a useful index for the secure system operation.

  • PDF

Voltage Stability Analysis Using Optimal Load Flow Method (최적화 조류계산법을 이용한 전압안정도 해석)

  • Jeon, Dong-Hoon;Choo, Jin-Boo;Kim, Kern-Joong;Lee, Byoung-Ill
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.50 no.7
    • /
    • pp.340-347
    • /
    • 2001
  • In this Paper, we proposed a new voltage stability analysis algorithm. Using $ $ calculated by the optimal load How method(OLF), it rapidly and correctly calculates a PV curve with voltage collapse point in the stable region. OLF can calculates voltage collapse point as well as the operating point in the stable region. Specially, $ $ indicates the relative distance between voltage collapse point and the solution in the unstable region. In the study of a sample system, we verified the superiority of proposed algorithm.

  • PDF

On-Line Calculation of the Critical Point of Voltage Collapse Based on Multiple Load Flow Solutions (다중조류계산을 이용한 전압붕괴 임계점의 On-Line 계산)

  • Nam, Hae-Kon;Kim, Dong-Jun
    • Proceedings of the KIEE Conference
    • /
    • 1993.07a
    • /
    • pp.134-136
    • /
    • 1993
  • This paper presents a novel and efficient method to calculate the critical point of voltage collapse. Conjugate gradient and modified Newton-Raphson methods are employed to calculate two pairs of multiple load flow solutions for two operating conditions, i.e., both +mode and -mode voltages for two loading conditions respectively. Then these four voltage magnitude-load data sets of the bus which is most susceptible to voltage collapse, are fitted to third order polynomial using Lagrangian interpolation in order to represent approximate nose curve (P-V curve). This nose curve locates first estimate of the critical point of voltage collapse. The procedure described above is repeated near the critical point and the new estimate will be very close to the critical point. The proposed method is tested for the eleven bus Klos-Kerner system, with good accuracy and fast computation time.

  • PDF

A Study on the Analysis and Control of Voltage Stability (전압안정성 분석 및 제어에 관한 연구)

  • 장수형;김규호;유석구
    • The Transactions of the Korean Institute of Electrical Engineers
    • /
    • v.43 no.6
    • /
    • pp.869-876
    • /
    • 1994
  • This paper presents an efficient method to calculate voltage collapse point and to avoid voltage instability. To evaluate voltage stability in power systems, it is necessary to get critical loading points. For this purpose, this paper uses linear programming to calculate efficiently voltage collapse point. Also, if index value becomes larger than given threshold value, voltage stability is improved by compensation of reactive power at selected bus. This algorithm is verified by simulation on the IEEE 14-bus sample system.

  • PDF

Quick and Accurate Computation of Voltage Stability Margin

  • Karbalaei, Farid;Abasi, Shahriar
    • Journal of Electrical Engineering and Technology
    • /
    • v.11 no.1
    • /
    • pp.1-8
    • /
    • 2016
  • It is well known that the behavior of PV curves is similar to a quadratic function. This is used in some papers to approximate PV curves and calculate the maximum-loading point by minimum number of power flow runs. This paper also based on quadratic approximation of the PV curves is aimed at completing previous works so that the computational efforts are reduced and the accuracy is maintained. To do this, an iterative method based on a quadratic function with two constant coefficients, instead of the three ones, is used. This simplifies the calculation of the quadratic function. In each iteration, to prevent the calculations from diverging, the equations are solved on the assumption that voltage magnitude at a selected load bus is known and the loading factor is unknown instead. The voltage magnitude except in the first iteration is selected equal to the one at the nose point of the latest approximated PV curve. A method is presented to put the mentioned voltage in the first iteration as close as possible to the collapse point voltage. This reduces the number of iterations needed to determine the maximum-loading point. This method is tested on four IEEE test systems.

Investigation of the Voltage Collapse Mechanism in Three-Phase PWM Rectifiers

  • Ren, Chunguang;Li, Huipeng;Yang, Yu;Han, Xiaoqing;Wang, Peng
    • Journal of Power Electronics
    • /
    • v.17 no.5
    • /
    • pp.1268-1277
    • /
    • 2017
  • Three-phase pulse width modulation (PWM) rectifiers are usually designed under the assumption of ideal ac power supply and input inductance. However, non-ideal circuit parameters may lead to a voltage collapse of PWM rectifiers. This paper investigates the mechanism of voltage collapse in three-phase PWM rectifiers. An analytical stability boundary expression is derived by analyzing the equilibrium point of the averaging state space model, which can not only accurately locate the voltage collapse boundary in the circuit parameter domain, but also reveal the essential characteristic of the voltage collapse. Results are obtained and compared with those of the trial-error method and the Jacobian method. Based on the analysis results, the system parameters can be divided into two categories. One of these categories affects the critical point, and other affects only the instability process. Furthermore, an effective control strategy is proposed to prevent a vulnerable system from being driven into the instability region. The analysis results are verified by the experiments.

An Intelligent System to Prevent Voltage Collapse for A Power system (전력계통의 전압 붕괴 방지를 위한 인텔리젼트 시스템)

  • Kim, Jae-Hyeon
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.50 no.10
    • /
    • pp.472-479
    • /
    • 2001
  • In order to prevent voltage collapse. this paper introduces the idea of the intelligent system and operating polices for a power system, then presents the results of voltage stability studies for that power system. The intelligent system includes a dedicated computer doing calculation and evaluation jobs and several intelligent relays serving as last guards to carry out the pre-set remedies. In the intelligent system, P-V curves are used to determine the operating margin from the current operating point to the maximum operating point, or the nose point. This paper suggests an operating guide for voltage stability of a power system. The effectiveness of location ad amount of load shedding for the different power load models are studied.

  • PDF

An Efficient Unified Method to Compute Voltage Collapse Point (전압붕괴 임계점 계산을 위한 효율적 통합법)

  • Nam, Hae-Gon;Kim, Dong-Jun;Song, Chung-Gi;Mun, Yeong-Hwan;Kim, Tae-Gyun;Lee, Hyo-Sang
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.48 no.8
    • /
    • pp.951-957
    • /
    • 1999
  • The saddle node bifurcation (SNB) and the distance voltage instability are valuable information in power system planning and operation. This paper presents a new efficient, robust and unified strategy to compute the SNB by the combined use of the continuation power flow (CPF), Point of Collapse (PoC) method, and the method of a pair of multiple load flow solutions (PMLFS) with Lagrange interpolation utilizing only their advantages: the approximate nose curves and critical loading are determined fast by Lagrange-interpolating two stable and two unstable solutions obtained by using the robust CPF and PMLFS; the exact SNB is computed by the quadratically converging PoC method. The proposed method has been tested on Klos-Kerner 11-bus, New England 30-bus, IEEE 118-bus and KEPCO 791-bus systems. The method is found to be so efficient that computation time for determining the SNB of the KEPCO 791-bus system is 17.82 sec by a notebook PC with 300 MHz Pentium processor.

  • PDF

Voltage Collapse Protection Considering Dynamics of Load (부하의 동특성을 고려한 TCSC에 의한 전압 붕괴의 예방)

  • Cho, J.H.;Son, K.M.;Lee, S.H.;Park, J.K.;Lee, B.H.
    • Proceedings of the KIEE Conference
    • /
    • 1995.11a
    • /
    • pp.110-112
    • /
    • 1995
  • Now days, voltage stability is well recognized as an important problem. It is well known that voltage stability is influenced by the characteristics of load. Up to present, voltage stability researches were done by the static load modeling, but it is needed that the precise analysis by the view point of dynamic load modeling. In this paper, with induction motor as dynamic load, I show the voltage collapse mechanism followed by load increase. Then I propose the protective method of voltage collapse by using TCSC.

  • PDF

A Study on the Analysis and Control of Voltage Stability (전압안정성 분석 및 제어에 관한 연구)

  • You, Seok-Koo;Kim, Kyu-Ho;Jang, Su-Hyeong
    • Proceedings of the KIEE Conference
    • /
    • 1993.07a
    • /
    • pp.64-66
    • /
    • 1993
  • This paper presents an efficient method to calculate voltage collapse point and to improve static voltage stability. To evaluate static voltage stability in power systems. it is necessary to get critical loading points. For this purpose, we use linear programming to calculate efficiently voltage collapse point. And if index value becomes larger than given threshold value, vol tags stability is improved by compensation of reactive power at selected bus. This algorithm is verified by simulation on the sample system.

  • PDF