• 한국융합학회논문지
• /
• 제2권4호
• /
• pp.21-27
• /
• 2011

현재 신 재생에너지 보급사업에 의해 설치되고 있는 태양광전원설비가 전력계통과 연계 운영될 경우 배전계통의 전력품질 요소에 어떠한 영향을 미치고 있는지를 모의시험을 통해 정확히 측정 분석하여 향후 분산형전원의 확대 보급에 따른 가이드라인의 구축과 기술적인 연계지침이 필요한 상황이다. 따라서 본 논문에서는 태양광이 연계되는 위치에 따른 선로임피던스($R{\pm}jX$)에 의하여 생기는 전압상승 및 하강에 의한 전력품질[Sag/Swell] 저하 현상에 대하여 태양광전원용 LabVIEW 프로그램을 통해 전력품질 시험을 수행하여 그 특성을 분석한다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 B
• /
• pp.965-967
• /
• 2001

전원 측 전압강하/상승 (Voltage sag/swell)을 보상하기 위한 동적전압보상기(Dynamic Voltage Restorer)등의 직렬 보상기에서 스위칭으로 인한 인버터 출력전압의 맥동(ripple)을 제거하기 위해 LC 필터가 사용된다. 본 논문에서는 LC 필터에서 커패시터의 전압을 상태 궤환을 이용하여 제어하는 알고리즘을 제시한다. LC 필터의 이산시간 상태 방정식을 구한 후, 궤환 이득값을 구하는 과정이 z-평면에서 이루어진다. 그리고, 제어기의 계산지연을 고려하여, 상태 관측기를 설계한다. 제안된 제어기는 기존 직렬보상기와 달리 전류 센서를 필요로 하지 않기 때문에 경제적인 이점을 가지게 된다.

• 전기학회논문지
• /
• 제58권5호
• /
• pp.936-943
• /
• 2009

Dynamic voltage restorer(DVR) is now more preferable enhancement than other power quality enhancement in industry to reduce the impact of voltage faults, especially voltage sags to sensitive loads. The main controllers for DVR consists of PLL(phase locked loop), compensation voltage calculator and voltage compensator. PLL detects the voltage faults and phase. Compensation voltage calculator calculates the reference voltage from the source voltage and phase. With calculated compensation voltage from PLL, voltage compensator restores the source voltage. If PLL detect ideal phase, compensation voltage calculator calculates ideal compensation voltage. Therefore, PLL for DVR is very important. This paper proposes the new method of PLL in DVR. First, the power circuit of DVR system is analyzed in order to compensate the voltage sags. Based on the analysis, new PLL for improving transient response of DVR is proposed. The proposed method uses band rejection filter(BRF) at q-axis in synchronous flame. In order to calculate compensation voltage in commercial instruments, the PQR theory is used. Proposed PLL method is demonstrated through simulation using Matlab-Simulink and experiment, and by checking load voltage, confirms operation of the DVR

• Journal of Electrical Engineering and Technology
• /
• 제13권2호
• /
• pp.790-799
• /
• 2018

This paper proposes a single-phase unified power quality conditioner (S-UPQC) for maintaining power quality issues in a microgrid. The S-UPQC can compensate the voltage and current harmonics, voltage sag, and swell as a dynamic voltage restorer (DVR), regardless of variations in the grid frequency. Odd harmonics are treated as even-order harmonics in a rotating frame to implement the harmonic compensators with only one repetitive controller (RC) without any harmonic extractor. The dynamic performance is improved and the delay time is reduced in the RC. The S-UPQC control scheme is designed to maintain accurate and stable operation under deviations of the grid frequency by using the Lagrange interpolation-based finite-impulse-response (LIFIR) filter approximation method. The proposed control schemes were validated through a simulation and experiment.

• 전기학회논문지
• /
• 제59권1호
• /
• pp.96-101
• /
• 2010

Superconducting Magnetic Energy Storage (SMES) system is one of the key technologies to overcome the voltage sag, swell, interruption and frequency fluctuation by fast response speed of current charge and discharge. In order to evaluate the characteristics of over mega joule class grid connected High Temperature Superconducting (HTS) SMES system, the authors proposed an algorithm by which the SMES coil could be connected to the Real Time Digital Simulator (RTDS). Using the proposed algorithm, users can perform the simulation of voltage sag and frequency stabilization with a real SMES coil in real time and easily change the capacity of SMES system as much as they need. To demonstrate the algorithm, real charge and discharge circuit and active load were manufactured and experimented. The results show that the current from real system was well amplified and applied to the current source of simulation circuit in real time.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.601_602
• /
• 2009

Superconducting Magnetic Energy Storage (SMES) system is one of the key technologies to overcome the voltage sag, swell, interruption and frequency fluctuation by fast response speed of current charge and discharge. In order to evaluate the characteristics of over mega joule class grid connected High Temperature Superconducting (HTS) SMES system, the authors proposed an algorithm by which the SMES coil could be connected to the Real Time Digital Simulator (RTDS). Using the proposed algorithm, users can perform the simulation of voltage sag and frequency stabilization with a real SMES coil in real time and easily change the capacity of SMES system as much as they need. To demonstrate the algorithm, real charge and discharge circuit and active load were manufactured and experimented. The results show that the current from real system was well amplified and applied to the current source of simulation circuit in real time.

• 한국전자통신학회논문지
• /
• 제16권2호
• /
• pp.293-300
• /
• 2021

본 연구에서는 SCDF를 사용하여 전력공급의 가치를 산정하고, 부하점별 중요도를 다면적인 평가를 하는 방법을 제시한다. 이의 방법으로 지속정전, 순간정전, 전압 Sag/Swell에 대응할 수 있는 SCDF를 제공하고, 이 SCDF를 사용하여 정전과 관련하여 어느 부하점에 어느 정도의 비용이 발생하는지를 계산하였으며, 이들 비용을 다면평가를 통해 어느 부분이 어느정도 취약한지를 평가하고 어느 부분의 확장이 필요한 지를 수치적으로 설명할 수 있도록 하였다. 본 연구를 우리나라의 실배전계통에 적용하여 평가하고 유용성을 검증하였다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
• /
• pp.251-255
• /
• 2003

This paper proposes a novel UPQC(unified power quality conditioner) based on H-bridge modules, isolated through single-phase multi-winding transformers. The dynamic performance of proposed system was analyzed by simulation with EMTDC/PSCAD, assuming that the UPQC is connected with the 22.9kV distribution line. The proposed system can be directly connected to the transmission line without series injection transformers. It has flexibility in expanding the operation voltage by increasing the number of H-bridge modules and can compensate reactive power, harmonics, voltage sag and swell, voltage unbalance. The control strategy for the proposing UPQC was derived using the instantaneous power method. The proposing UPQC has the ultimate capability of improving power quality at the point of installation on power distribution systems and can be utilized for the future distribution system.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2005년도 전력전자학술대회 논문집
• /
• pp.552-554
• /
• 2005

This paper deals with a simple structured voltage disturbance generator for power quality improving devices. The proposed generator can be applied to the performance test of custom power devices. Voltage sag, swell, outage, unbalance and phase jump after outage are provided by the generator. The improving phase jump operating principle of the generator is described and analysed. The usefulness of the generator is verified through simulation.

• 대한전기학회논문지:전력기술부문A
• /
• 제54권1호
• /
• pp.1-7
• /
• 2005

This paper proposes a novel UPQC(unified power quality conditioner) based on H-bridge modules, isolated through single-phase multi-winding transformers. The dynamic performance of proposed system was analyzed by simulation with PSCAD/EMTDC, assuming that the UPQC is connected with the 22.9kV distribution line. The proposed system can be directly connected to the transmission line without series injection transformers. It has flexibility in expanding the operation voltage by increasing the number of H-bridge modules and can compensate reactive power, harmonics, voltage sag and swell, voltage unbalance. The proposing UPQC has the ultimate capability of improving power quality at the point of installation on power distribution systems.