• Journal of Power Electronics
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• v.4 no.2
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• pp.65-76
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• 2004

In this paper, the steady-state analysis of the three-phase self-excited induction generator (SEIG) driven by a variable-speed prime mover (VSPM) such as a wind turbine is presented. The steady-state torque-speed characteristics of the VSPM are considered with the three-phase SEIG equivalent circuit for evaluating the operating performances due to the inductive load variations. Furthermore, a PI closed-loop feedback voltage regulation scheme based on the static VAR compensator (SVC) for the three-phase SEIG driven by the VSPM is designed and considered for the wind power generation conditioner. The simulation and experimental results prove the practical effectiveness of the additional SVC with the PI controller-based feedback loop in terms of fast response and high performances.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.10
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• pp.500-506
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• 2005

With the advent of electric power systems moving to a deregulated retail electricity market environment, calculating distribution service tariffs has become a challenging theme for distribution industries and tariff regulators. As distribution business remains as a monopoly, it is necessary to be regulated. And as multiple distribution companies compete with each other, it would be efficient to adopt competition to the determination of distribution service tariffs. This paper proposes a method to calculate distribution service tariffs using yardstick regulation, which can lead to competition among multiple distribution companies. The proposed method takes into account not only recovering revenue requirements but also the advantages of the yardstick regulation based on long-term marginal costs of distribution network expansion algorithms. A computer simulation is carried out to illustrate effectiveness of the proposed method and it is estimated that the algorithm can be applied to compute the distribution service tariffs under retail electricity markets.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.53-61
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• 2009

This paper presents the improved voltage regulation method in power distribution system with multiple PV systems. At present, Line Drop Compensator (LDC) method has been used as voltage regulation method of power distribution system, which regulates the voltage using Under Load Tap Changer (ULTC), regarding the power flow of distribution system as one way. However, the method may be not able to regulate the voltage in a permissible range when the power flow is two ways. Thus, in this paper, we present the improved voltage regulation method of power distribution system using the voltage data of the point connected PV systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.622-628
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• 2014

This paper presents the SOC-based control strategy of BESS(Battery Energy Storage System) for providing power system frequency regulation in the bulk power systems. As the life cycle of BESS would be shortened by frequent changes of charge and discharge required for frequency regulation in a steady state, the proposed algorithm operates BESS within a range of SOC where its life cycle can be maximized. However, during a transient period of which occurrence frequency is low, BESS would be controlled to use its full capacity in a wider range of SOC. In addition, each output of multiple BESS is proportionally determined by its SOC so that the balance in SOC of multiple BESS can be managed. The effectiveness of the proposed control strategy is verified through various case studies employing a test system. Moreover, the control result of BESS with the measured frequency from a real system shows SOC of BESS can be maintained within a specific range although the frequency deviation is biased.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.125-126
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• 2013

ESS(Energy Storage System) for Improve the quality of the power grid, supply reliability, system stability and the efficient operation method of power is drawing attention. According to changes in the load of the power system frequency will be adjustable in real time in response to changes in the frequency of the grid, so thermal power output is mainly controlled in order to keep the grid frequency stable. ESS for adjusting the frequency of the grid when the frequency rises to grid and charge the energy storage device. If the frequency drops to discharge the battery power to the grid and the future is expected to replace the thermal power plant. This paper describes 4MW ESS for the frequency regulation and find out about the characteristics through the PSCAD/EMTDC.

• Journal of Power Electronics
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• v.10 no.1
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• pp.91-96
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• 2010

In this paper, a simplified control algorithm for a three-phase, four-wire unified power quality conditioner (UPQC) is presented to compensate for supply voltage distortions/unbalance, supply current harmonics, the supply neutral current, the reactive power and the load unbalance as well as to maintain zero voltage regulation (ZVR) at the point of common coupling (PCC). The UPQC is realized by the integration of series and shunt active filters (AFs) sharing a common dc bus capacitor. The shunt AF is realized using a three-phase, four leg voltage source inverter (VSI) and the series AF is realized using a three-phase, three leg VSI. A dynamic model of the UPQC is developed in the MATLAB/SIMULINK environment and the simulation results demonstrating the power quality improvement in the system are presented for different supply and load conditions.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.740-742
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• 1999

The demand for the high quality of utility electrical power has been increasing rapidly in recent years because of today's electrical energy dependent industries and most people's everyday lives based on computer systems. However, electrical power supply conditions to meet this high quality demand becomes more difficult and more due to a large portion of nuclear power plants output in total electrical power supply which normally do not respond to frequency variations, and high peak of air conditioner demands during the summer season. So the rest of power plants should be operated to show the best governor regulation performance to maintain the electrical power frequency quality.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.425-426
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• 2012

기존 1차 측 제어(Primary Side Regulation: PSR) 방식 중 최고의 성능을 보이는 i사의 방식은 DCM에서 동작하는 전류가 0A에 도달했을 때 3차 권선을 통해 1차 측에서 출력전압을 검출하는 방식이다. 기존 방식은 전류가 0A가 되는 시점을 예측하여 검출하는 방법을 사용하기 때문에 트랜스포머의 자화인덕턴스 값의 허용오차에 따라 변동 폭이 커질 수 있다. 본 논문에서는 자화인덕턴스의 크기에 관계없이 기존 방식보다 더 정확하게 검출하는 방법을 제시하고, PSIM을 사용한 모의실험을 통하여 검증한다.

• KEPCO Journal on Electric Power and Energy
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• v.4 no.2
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• pp.107-114
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• 2018

In recent years, ESS (Energy Storage System) has been widely used in various parts of a power system. Especially, due to its fast response time and high ramp rate, ESS is known to play an important role in regulating grid frequency and providing rotational inertia. As the number of installed and commercially operating ESSs increases, the reliability becomes an important issue. This paper introduces control schemes and presents its test method for grid-connected ESS for primary frequency regulation. The test method allows to verify the control operation in the individual operation mode and state. A validation of the method through actual ESS test in a electrical substation is presented in the case study section.

• Environmental and Resource Economics Review
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• v.11 no.2
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• pp.233-260
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• 2002

This paper tries to analyze the efficiency structure and regulatory effects in electric power industry by using total factor productivity and indices based on cost function method. This paper performed an empirical analysis on the efficiency improvement and optimal scale taking the cost aspect in electricity industry into account. By expanding the cost structure framework, this paper proposes the analytical method regarding the needs of technology regulation and presents the empirical results which can be verified. Hence, this work can play a key role in decision-making of the national power development and regulatory policy. The empirical result indicates that the electricity industry in Korea has been in the state of economies of scale until 1980s, However, due to sustained growth of power generation, economies of scale declined and subsided after 1980s and then diseconomies of scale is shown recent years. The analysis on the effect of technology regulation shows the national large-scale base-load power plant development-oriented policy until so far contributed substantial cost effect to the electricity industry. The empirical result indicates that the reserve requirement as one of means of technology regulation policy did not contribute to the economies of scale but positive effect on the total factor productivity in Korea.