• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.592-597
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• 2019

A conventional method to improve transient stability in power system is the use of reactive power compensation devices such as STATCOM and SVC. However, this traditional method cannot prevent a rapid voltage collapse brought on by motors stalling due to system fault. On the other hand, ESS(Energy Storage System) provides fast-acting, flexible reactive and active power control. The fast active power compensation with energy storage system plays a significant role in transient stability enhancement after a major fault of power system. In this paper, transient stability enhancement method by using energy storage system is proposed for the power system including a dynamic load such as large motor. The effectiveness of energy storage system compared to conventional devices in enhancing transient stability of power system is presented. The results of simulations show that the simultaneous injection of active and reactive power can enhance more effectively transient stability.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.4
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• pp.341-347
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• 2001

Harmonics and fundamental reactive current of nonlinear loads in serious unbalanced power condition, are compensated by current synchronous detection(CSD) theory which is also acceptable for single phase power system. But, the CSD theory is not suitable any more, in case of controlled independently harmonics and reactive component. Therefore, a new algorithm, the expanded current synchronous detection(ECSD) theory for a three phase active power filter based on decomposition of fundamental reactive, distorted components, is proposed in this paper. The proposed ECSD theory is experimented and tested comparison with a few power theories under asymmetrical condition in power system.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2481-2483
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• 1999

This paper proposed the p-q-r coordinate system where the instantaneous active power p, and the two instantaneous reactive powers $q_{q}$, $q_{r}$ 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 storage element.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.131-133
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• 1998

This paper, proposed the p-q-r coordinate system where the instantaneous active power p, and the two instantaneous reactive powers $q_{q}$, $q_{r}$ 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 the three-phase four-wire system can be eliminated by only compensating the instantaneous reactive power using no energy storage element.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1174-1176
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• 2000

This paper presents a new control strategy of the active power filter to compensate the fundamental and high order reactive power. Using the proposed control strategy, the calculation of active and reactive power of the load is not required. So the system configurations and the controller can be constructed very simply. To decrease the load of active power filter, the LC passive filter bank can be used without any additional strategy. In this paper, the algorithm of the proposed new control strategy is discussed and the experimental results are shown.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.3
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• pp.14-16
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• 1999

This paper gives a basic data of fluorescent lamp equiprrents for calculating of receiving capacity. The fluorescent lamp equiprrent has non-linear cl1arocteristics of the active and the reactive power variation. Therefore we need real measurerrents. We tested and rreasured active and reactive power of fluorescent lamp equiprrents which use 4O[W] lamps and various ballasts. The potential variation range is A.C. 200~240[V].240[V].

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.453-454
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• 2016

The ESS(Energy Storage System) connected with distributed generation is drawing attention due to improving the quality load leveling, peak shaving for enhancing reliability of the power grid. The grid-connected inverter makes frequency adjustment to the active power's charge discharge according to the load variation. In addition, the inverter is possible to act as a reactive power compensation device to eliminate harmonic operates as power factor change inhibiting, anti-transient voltage fluctuation, active filter. In this paper, we propose a design method of igbt stack considering the reactive power supply capacity to improve the quality and reliability of the inverter. Moreover, the grid-connected inverter considering the four-quadrant rated operation designed stack and verified the feasibility of the design through a thermal analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.5
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• pp.936-941
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• 2011

Generation cooperations have focused on active power directly related to economic value. So, utility cooperation have taken expense to stabilize power system, although generator has responded quickly with variation of power system voltage and is controlled at real time. As a reactive power source, it is necessary for generator's capabilities to be verified. But domestic generators scarcely have been tested and operated to reactive power capability. In case of power system fault, operators would not quickly take a follow-up actions about reactive power disturbance. Therefore generator reactive power capability verification strategy must be developed, several generators is tested as examples since 2004. This paper is extracted from the test results.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.365-366
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• 2015

Shunt active power filter is a complete current source which can provide an effective and adjustable solution for elimination of harmonic currents in power system. Its performance depends on strategy employed in reference current generation, control technique and topology of converter used in the design.[1-2]. In this paper Three Phase Six switch Z-source rectifier with active power filtering capability based on instantaneous reactive power theory is described. Thanking to the theory power factor and THD value are significantly improved. Experiment results and conclusions are presented.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.611-616
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• 2018

In the cost based pool market in Korea, there is no compensation of reactive power because the fuel cost for reactive power is relatively low compared to that of active power. However, the change of energy paradigm in the future, such as widespread integration of distributed renewable energy source, will prevent the system operator from mandating the reactive power supply without any compensation. Thus, in this study, we propose the reference voltage of the 345 kV transmission system that minimizes the reactive power supply. This is closely related to the economic dispatch of reactive power aiming at minimizing the compensation cost for the reactive power service. In order to verify the effectiveness of the proposed reference voltage, the simulations are performed using the IEEE 14 bus system and the KEPCO real networks. The simulation results show that a voltage lower than the current reference value is recommended to reduce the reactive power supply and also suggest that the current voltage specification for the 345 kV system needs to be reviewed.