• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.304-305
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• 2006

Now there is utilization of elevator increasing continuously, it is one of electrical facilities taking a serious view safety. However, elevator comfortable ride is researched generally Recently aging condition, equipment life, malfunction, other applicancies of power electronics and equipment disturbance effect on power quality and prevention measures are much researches in advanced nation. but awareness is lacking real condition up to now in domestic. Voltage sag, swell, harmonics, surge etc of elevator system is important problem about human safety. and there are many quality compensation to solve these problem of elevator. So to evaluate these problem, in this paper, displayed result through computer simulation for converter of problem, and inverter part by power quality problem in power distribution system.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.453-455
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• 2006

This paper presents about recognition power quality problems using neural network. Neural network is a very powerful way to detect and classify power quality problems. But the transient like as very fast problems is difficult event to recognize. Wavelet transform is appropriate method for detecting signal irregularities. So we make features from wavelet transform. Finally we get high efficiency for detecting and classifying almost all power quality problems.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.180-181
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• 2019

This paper proposes a method for improving the power quality of PMSG-based wind energy conversion system based on model predictive control in DC Microgrid. The MPC has a fast dynamic response. However, a large torque ripple deteriorating power quality is generated by a large and fixed switching period. On the other hand, the proposed method improves the power quality by setting the sampling time having zero torque error. The validity of the proposed method is verified through PSIM simulation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.12
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• pp.561-566
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• 2005

This paper introduces a compression technique for power qualify disturbance signal via discrete wavelet transform(DWT). The proposed approach is based on a previous estimation of the stationary component of power quality disturbance signal, so that it could be subtracted from the original signal in order to reduce a dynamic range of signal and generate transient events signal, which is subsequently applied to the compression technique. The compression techniques is performed through the difference signal decomposition, thresholding of wavelet coefficients, and signal reconstruction. It presents the relation between compression efficiency and threshold. It shouts that the wavelet transform leads to a power quality data compression approach with high compression efficiency, small compression error and good de-nosing effect.

• Journal of Information Processing Systems
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• v.15 no.1
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• pp.116-126
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• 2019

In this paper, an improved one-against-one support vector machine algorithm is used to classify multiple power quality disturbances. To solve the problem of parameter selection, an improved particle swarm optimization algorithm is proposed to optimize the parameters of the support vector machine. By proposing a new inertia weight expression, the particle swarm optimization algorithm can effectively conduct a global search at the outset and effectively search locally later in a study, which improves the overall classification accuracy. The experimental results show that the improved particle swarm optimization method is more accurate than a grid search algorithm optimization and other improved particle swarm optimizations with regard to its classification of multiple power quality disturbances. Furthermore, the number of support vectors is reduced.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.5
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• pp.485-493
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• 2011

In Korea, PM (Particulate Matter) emissions caused by coal-fired power plants are measured by a system, so called Clean Air Policy Support System (CAPSS), which uses foreign emission factors. However, the system fails to reflect the characteristics of domestic power plants. In this regard, this study aims to develop local, accurate domestic emission factors. The study measured the amount of TSP (Total Suspended Particulates), PM10 and PM2.5 by collecting samples from the latter parts of pollution control devices which were installed at 3 bituminous-fired power plants and 3 anthracite-fired power plants. The results showed that the average concentrations of TSP, PM10 and PM2.5 measured at bituminous-fired power plants were 4.63 mg/$Sm^3$, 2.96 mg/$Sm^3$ and 3.07 mg/$Sm^3$ respectively, much higher than those from anthracite-fired power plants (2.96 mg/$Sm^3$, 2.47 mg/$Sm^3$ and 1.37 mg/$Sm^3$, respectively). In addition, bituminous-fired power plants showed higher ratios of PM10/TSP and PM2.5/TSP with 0.66 and 0.92, respectively, compared to 0.82 and 0.46, the ratios of PM10/TSP and PM2.5/TSP measured in anthracite-fired power plants. Emission factors based-on concentration measurements were also higher for bituminous-fired power plants, and PM with smaller particles tended to have bigger difference in emission factors between the two fuels. This study calculated the amount of PM emissions by using the estimated emission factors. When it comes to the PM emissions, it was less than that of CAPSS while similar to that of CleanSYS in its amount. It is expected that the emission factors developed by this study will be used in Korea replacing foreign emission factors currently used in Korea by ensuring the objectivity and reliability as domestic emission factors.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.7
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• pp.52-58
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• 2012

In this study, we have investigated the effect of the solar power generation facilities on the power quality of interconnected solar power generation system. When the solar power generation facility was connected to the distribution system, whether the solar power generation is under operation or not, Peak factor of current was increased to 0.033[%], Frequency is deviated from $60{\pm}0.2$[Hz] and also Short term flicker indication($P_{st}$) increased to 0.213[p.u.] compare with the disconnected situation. Harmonic current [%] in orders was 11.42[%] maximum under 11th orders and was 7.861[%] between 11th and 17th orders. These values were about 3 or 4 times compared with "the power system interconnection technique standards" at the same situation above. Therefore, we could confirmed that the solar power generation facility, when it was connected to the existing distribution system, made bad influence on the power qualities such as the peak factor of current, frequency regulation, short term flicker indication($P_{st}$) and harmonic current [%] in orders etc.

• Journal of Power Electronics
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• v.6 no.4
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• pp.307-314
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• 2006

This paper presents a wavelet and neural network based technology for the monitoring and classification of various types of power quality (PQ) disturbances. Simultaneous and automatic detection and classification of PQ transients, is recommended, however these processes have not been thoroughly investigated so far. In this paper, the hardware and software of a power quality data acquisition system (PQDAS) is described. In this system, an auto-classifying system combines the properties of the wavelet transform with the advantages of a neural network. Additionally, to improve recognition rate, extraction technology is considered.

• Journal of Power Electronics
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• v.8 no.3
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• pp.259-267
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• 2008

Power quality improvement in a three-phase four-wire system is achieved using a new topology of DSTATCOM (distribution static compensator) consisting of a star/delta transformer with a tertiary winding and a three-leg VSC (voltage source converter). This new topology of DSTATCOM is proposed for power factor correction or voltage regulation along with harmonic elimination, load balancing and neutral current compensation. A tertiary winding is introduced in each phase for a delta connected secondary in addition to the star-star windings and this delta connected winding is responsible for neutral current compensation. The dynamic performance of the proposed DSTATCOM system is demonstrated using MATLAB with its Simulink and Power System Blockset (PSB) toolboxes under varying loads. The capacitor supported DC bus of the DSTATCOM is regulated to the reference voltage under varying loads.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.760-763
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• 2004

The recent growth in the use of impactive and nonlinear loads, electronic, and medical devices sensitive to power quality has caused many power quality problems and power supply-and-demand problem. Recently, in power system not only the reliability of the power supply but also the DVR(Dynamic Voltage Restorer), UPS, and APF are being studied more and more. Hence, in this paper, Voltage sag detection algorithm for voltage sag corrector is proposed. Also, simple circuit for the experimental voltage sag is Introduced.