• 전기학회논문지
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• 제63권10호
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• pp.1347-1353
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• 2014

This paper researches a modeling and experiment of 50kW diesel generator in grid-connected mode. The output of diesel generator can be calculated by the phase difference between voltage and current as well as the diesel generator parameter such as mutual impedance, field current and rotor angle. Considering the different d-q frame impedance, the output of diesel generator is analyzed for equation and verified by simulation. The diesel generator modeled by considering the time delay for actuator, diesel engine and exciter. The controller of diesel generator is divided into governor and exciter. The governor consists of speed controller and active power controller, where speed controller maintains frequency as 60Hz and active power tracks active power reference. On the other hand, the exciter consists of voltage controller and reactive power controller, where voltage controller controls $380V_{LL}$ and reactive power is controlled as zero. When the active power reference is changed as 0.1pu in the grid connected mode, the active power takes 10 seconds to reach the steady state and the reactive power is maintains as zero. The 50kW diesel generator is tested and experiment results are well matched with the simulation results.

• 조명전기설비학회논문지
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• 제14권3호
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• pp.77-80
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• 2000

본 논문은 有無效 섣둡jJ設觸의 投貴위치와 그 용향을 적정화하여 동일한 설비투자량에 대하여 전력손실을 최소화하는 방안에 대하여 설명하였다. 유효 및 무효전릭의 미소증분에 대한 손실의 변화를 나타내는 모선의 손실감도를 소개하고 전력송실을 최대한 개선하기 워한 유무효전력 설비의 투자지표로 이용하였다. 각 모선에 주어지는 투자지표의 우선순위에 따라 유효 및 무효전력설비가 투자되어 전력손실을 최소화한다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권12호
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• pp.715-726
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• 1999

This paper estimates the capacity of shunt type active power filters(APF) for harmonic/reactive power compensation with a thyristor converter load. The base capacity requirement of APF is defined for idealized converter load current waveform and the effect of commutation overlap on the APF capacity is examined. The APF capacity required for reactive power compensation in addition to the harmonic elimination is estimated to give maximum achievable power factor for various operating condition of the partially-loaded thyristor converter. The method of current limit of APF is introduced, and it is shown that the APF capacity can be considerably reduced by deliberately limiting the peak current while maintaining the filtering performance to meet the level std 519 regulation.

• Journal of Power Electronics
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• 제18권6호
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• pp.1855-1865
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• 2018

This paper presents a control strategy for voltage-controlled multi-function distributed generation (DG) combined with an active power filter (APF) and a reactive power compensator. The control strategy is based on droop control. As a result of local nonlinear loads, the voltages of the point of common coupling (PCC) and the currents injecting into the grid by the DG are distorted. The power quality of the PCC voltage can be enhanced by using PCC harmonic compensation. In addition, with the PCC harmonic compensation, the DG offers a low-impedance path for harmonic currents. Therefore, the DG absorbs most of the harmonic currents generated by local loads, and the total harmonic distortion (THD) of the grid connected current is dramatically reduced. Furthermore, by regulating the reactive power of the DG, the magnitude of the PCC voltage can be maintained at its nominal value. The performance of the DG with the proposed control strategy is analyzed by bode diagrams. Finally, simulation and experimental results verify the proposed control strategy.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권3호
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• pp.211-218
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• 2000

The performance and dynamic characteristics of three-phase active power filter with PCC voltage compensation is presented and analyzed in this paper. The characteristics of parallel active filter are discussed when they are applied to nonlinear loads with current source and voltage source type, the characteristics of voltage compensator and comparison of two functions are discussed. The proposed scheme in this paper employs a PWM voltage-source inverter and has two operation modes. First, it operates as a conventional active filter with reactive power compensation while PCC voltage is in a certain range. Second, is operates as a voltage compensator while PCC voltage is out of range. Finally, the validity of this scheme is investigated through analysis of simulation and experimental results for a prototype active power filter system rated at 10KVA.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.291-294
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• 1998

This paper presents a new active power filter with low DC voltage for compensating reactive power and harmonics of three-phase high power/voltage harmonic producing load. It has a structure of converter connected in series with power factor correction capacitor. Appropriate size and number of filter capacitor are determined by an equation and applied to simulation of 10kvar 6-pulse SCR rectifier.

• 전기학회논문지
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• 제61권3호
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• pp.355-360
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• 2012

It is difficult to converge power flow for the power system planning data. The main cause of power flow diverse is reactive power imbalance. A active power could be adjust by ELD or merit order but a reactive power couldn't dispatch before power flow analysis. The lack of reactive power of power system is cause a inadequate voltage drop This paper suggest new reactive power dispatch algorithm using switched shunt admittance. This algorithm uses reactive power sensitivity called switch shunt jacobian. When proposed algorithm applies to real system data that couldn't be conversed in PSS/E the power flow analysis is converged.

• 전기학회논문지
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• 제57권8호
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• pp.1377-1382
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• 2008

DSTATCOM(distribution static compensator) is one of the custom power devices, and protects a distribution line from unbalanced and harmonic current caused by non-linear and unbalanced loads. Researches about DSTATCOM are mainly divided two parts, one is the calculation of compensation current and the other part is the current control. Conventional researches use a LPF(low pass filter) to eliminate ripple component at the calculation of compensation current. But this method has a problem that LPF's characteristics restrict the compensation performance of instantaneous active and reactive power. This paper proposes a calculation of compensation current using state observer that can be a counterproposal of conventional methods using LPF. Improved performance of instantaneous active and reactive power compensation was shown by experiments.

• KIEE International Transactions on Power Engineering
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• 제4A권4호
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• pp.262-267
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• 2004

With the advent of electric power systems moving from a vertically integrated structure to a deregulated environment, calculating reactive power service charges has become a new and challenging theme for market operators. This paper examines various methods for reactive power management adopted throughout various deregulated foreign and domestic markets and then proposes an innovative method to calculate reactive power service charges using a reactive power market in a wholesale electricity market. The reactive power market is operated based on bids from the generating sources and it settles on uniform prices by running the reactive OPF programs of the day-ahead electricity market. The proposed method takes into account recovering not only the costs of installed capacity but also the lost opportunity costs incurred by reducing active power output to increase reactive power production. Based on the result of the reactive OPF program, the generators that produce reactive power within the obligatory range do not make payments whereas the generators producing reactive power beyond the obligatory range receive compensation by the price determined in the market. A numerical sample study is carried out to illustrate the processes and appropriateness of the proposed method.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1380-1388
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• 2013

The conventional graphical representation of the instantaneous compensation power flow for single-phase active power filters(APFs) simply represents the active power flow and the reactive power flow which flowing between the power source and the active filter / the load. But, this method does not provide the information about the rectification mode and the compensation mode of APFs, especially, the loss for each mode was not considered at all. This is very important to understand the compensation operation characteristics of APFs. Therefore, this paper proposes the graphical representation of the instantaneous compensation power flow for single-phase APFs considering the instantaneous rectification mode and the instantaneous inversion mode. Three cases are verified in this paper - without compensation, with compensation of the active power 'p' and the fundamental reactive power 'q', and with compensation of only the distorted power 'h'. To ensure the validity of the proposed approach, PSIM simulation is achieved. As a result, we could confirm that the proposed approach was easy to explain the instantaneous compensation power flow considering the instantaneous rectification mode and the instantaneous inversion mode of APFs, also, Total Harmonic Distortion(THD)/Power Factor (P.F) and Fast Fourier Transform(FFT) analysis were compared for each case.