• Journal of Electrical Engineering and Technology
• /
• 제3권1호
• /
• pp.1-7
• /
• 2008

Superconducting Magnetic Energy Storage (SMES) can inject or absorb real and reactive power to or from a power system at a very fast rate on a repetitive basis. These characteristics make the application of SMES ideal for transmission grid control and stability enhancement. The purpose of this paper is to introduce the SMES model and scheme to control the active and reactive power through the power electronic device. Furthermore, an optimal priority scheme is proposed for the combination of active and reactive power control to be able to stabilize power transient swings.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 A
• /
• pp.350-353
• /
• 2000

This paper presents an algorithm for Optimal Reactive Power Dispatch(ORPD) problem based on genetic algorithm. Optimal reactive power dispatch is particularized to the minimization of transmission line losses by suitable selection of generator reactive power outputs and transformer tap settings. To reduce system loss and improve voltage profile, two methods, Loss Re-Distribution Algorithm (LRDA) and Voltage Dependent Load Model (VDLM), are applied to ORPD. The proposed methods have been evaluated on the IEEE 30 bus system. Each of results have been compared with result of load flow.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
• /
• pp.1093-1096
• /
• 2002

In this paper, a novel multi voltage inverter system is proposed for reductions of harmonics, which can compensate reactive power. At first, we remove capacitor at input side for reactive power compensation. Secondly, by adding DC voltage to the filter capacitor, it can control power factors as lead-phase according to alterations of loads at power reception. Thirdly, if winding and single phase-bridge inverter(auxiliary circuit) is installed to DC power for reduction of harmonic, waveform of output voltages become to 36-steps. Thus, SVC(static var compensator) systems which can reduce harmonics are designed.

• 제어로봇시스템학회논문지
• /
• 제4권4호
• /
• pp.517-524
• /
• 1998

This paper discusses the development of a reactive power controller using digital signal processing. Digital Signal Processing is the technique of using digital devices to Process continuous signals or data, often in real-time. And DSP algorithms are associated with a discrete time interval between input samples. When one designs a digital filter, one can use a Laplace transform to determine the continuous time frequency response. The corresponding discrete time transform is called Z transform and depends upon discrete samples of the input spaced equally in time. The objectives of this paper are to minimize real power losses and improve the power factor of a given system. Also, the implementation of a direct-form non recursive filter on the TMS320C31 has been described. The application of this microprocessor-based controller using DSP on test system reveals its numerous advantages. Performance and features of the controller for the reactive power control are analyzed.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제48권6호
• /
• pp.330-335
• /
• 1999

This paper proposed the p-q-r coordinate system where the instantaneous active power p, and the two instantaneous reactive powers qq, qr were defined. The three power components are linearly independent, so the compensation for the two instantaneous reactive powers leads to control the two components of the current space vector. With the theory, the neutral current of a three-phase four-wire system can be eliminated by only compensating the instantaneous reactive power using no energy storge element.

• 로봇학회논문지
• /
• 제2권2호
• /
• pp.119-128
• /
• 2007

Emotion interaction between human and robot is an important element for natural interaction especially for service robot. We propose a hybrid emotion generation architecture and detailed design of reactive process in the architecture based on insight about human emotion system. Reactive emotion generation is to increase task performance and believability of the service robot. Experiment result shows that it seems possible for the reactive process to function for those purposes, and reciprocal interaction between different layers is important for proper functioning of robot's emotion generation system.

• 대한전기학회논문지
• /
• 제38권10호
• /
• pp.805-810
• /
• 1989

This paper presents a method for planning reactive power compensation such as shunt capacitors and reacters so as to maintain bus voltage in acceptable range during steady state operation in power system. The algorithm in this paper decomposes the problem into reactive power planning module for the compensation of bus voltage and load flow module for adjusting the error resulted from the linear approximation. A planning technique is based on linear programming to minimize the amount of added reactive power compensation in each case. Transformer tap settings and generator voltages are adjusted to minimize the compensation. The constraints are the operation limits of the control variables and bus voltages. The result of one sample system is presented to confirm the practical use of the proposed algorithm.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 A
• /
• pp.168-170
• /
• 2001

This paper presents the strategy of reactive power compensation which directly improves voltage stability. Voltage stability index that serves as an indirect assessment of voltage stability margin is derived from M.G.C.F. (Modified Generalized Curve Fit) algorithm incorporating load model. Weak buses are ranked by this stability index, and amounts of reactive power compensation are determined by function of reactive power and stability index. Using the proposed strategy, all load buses can be prevented from voltage collapse gradually. A simple illustrative example is given as well as simulation results obtained on 5 bus test system and 19 bus real power system.

• 대한전기학회논문지
• /
• 제33권10호
• /
• pp.410-422
• /
• 1984

This paper presents a new practical method for optimal active and reactive power control for the economic operation in electrical power system, and the programs are developed for digital computer solution. The major features and techniques of this paper are as follows: 1) The method is presented for finding the equivalent active power balance equation applying the sparse Jacobian matrix of power flow equation instead of using B constant as active power balance equation considering transmission loss, and thus for determining directly optimal active power allocation berween generator unitw satisfying the equality and inequality constraints. 2) The method is proposed for solving directly the optimum economim dispatch problem without using gradient method and penalty function for both active and reactive power control. As a result, the computing time are reduced and convergence characteristic is remarkably improved. 3) Unlike most of conventional methods which adopt the transmission loss as a objective function for reactive power control, the total fuel cost of themal power plant is adopted as objective function for both active and reactive power control. consequently, more reasonable and economic profit can be achieved.

• Journal of Electrical Engineering and Technology
• /
• 제9권2호
• /
• pp.399-405
• /
• 2014

For stable integration of large-scale wind farms, integration standards (Grid codes) have been proposed by the system operator. In particular, voltage control of large-scale wind farms is gradually becoming important because of the increasing size of individual wind farms. Among the various voltage control methods, Secondary Voltage Control (SVC) is a method that can control the reactive power reserve of a control area uniformly. This paper proposes hybrid SVC when a large-scale wind farm is integrated into the power grid. Using SVC, the burden of a wind turbine converter for generating reactive power can be reduced. To prove the effectiveness of the proposed strategy, a simulation study is carried out for the Jeju system. The proposed strategy can improve the voltage conditions and reactive power reserve with this hybrid SVC.