전류형 HVDC 성능 개선에 대한 연구 (STATCOM를 중점으로)

배영재 ( Young-jae Bae ),천관호 ( Kwan-ho Chun ) 사단법인 한국빅데이터서비스학회 2023 빅데이터서비스학회 논문집 Vol.1 No.2

우리나라 HVDC 시스템은 제주1호기, 2호기에 이어 제주와 육지간 HVDC와 북당진-고덕 HVDC, 동해안 HVDC를 계획하고 있다. 특히 북당진-고덕 HVDC 시스템은 Back to Back scheme 특성 가지며, 이벤트 발생 시 HVDC Run-up기능을 동작하면, 낮은 DC 전압으로 인해 DC 전력이 목표치에 상승하지 못하는 문제가 발생한다. 북당진-고덕 HVDC의 고덕 측의 TOV(Temporary Over Voltage)의 문제를 해결하기 위해 STATCOM을 설치하였다. 실시간 계통해석 시뮬레이터(RTDS)를 이용하여 전압원 모델을 HVDC 양 단에 설치하고 인버터단에 STATCOM을 투입하여 시뮬레이션 하였다. STATCOM의 AC전압을 유지시키려는 특성으로 인해 투입 전보다 DC 전력이 상승하지 못하는 결과를 보여, STATCOM의 Vset 전압을 높여, AC 전압, DC 전압 또한 상승시켜, DC 전력을 목표치까지 출력하는것을 확인하였다.향후에는 우리나라 전계통을 이용하여, 765kV 선로로 시뮬레이션하여 이벤트 발생 시 STATCOM 의 설정전압에 대해 정밀한 모의가 필요하고, 동해안 HVDC 구축 시 두 HVDC의 모의시뮬레이션이 필요하다. Following Jeju Units 1 and 2, Korea’s HVDC system is planning HVDC between Jeju and the mainland, HVDC between Bukdangjin and Godeok, and HVDC on the east coast. In particular, the Bukdangjin-Godeok HVDC system has a Back to Back scheme characteristic, and when the HVDC Run-up function is activated when an event occurs, a problem occurs in which DC power does not rise to the target value due to low DC voltage. STATCOM was installed to solve the TOV (Temporary Over Voltage) problem on the Godeok side of the Bukdangjin-Godeok HVDC. Using a real-time system analysis simulator (RTDS), a voltage source model was installed on both ends of the HVDC and STATCOM was input into the inverter for simulation. Due to the characteristic of STATCOM trying to maintain the AC voltage, the DC power did not increase compared to before input, so by increasing the Vset voltage of STATCOM, the AC voltage and DC voltage were also increased, and it was confirmed that the DC power was output up to the target value. In the future, Using Korea’s electric system, a 765kV line is simulated to accurately simulate the set voltage of STATCOM when an event occurs, and when constructing an East Coast HVDC, the correlation between two HVDCs is needed to be simulated.

Modeling and Dynamic Analysis of STATCOM for Short-Term Voltage Stability Improvement using EMTP/RV

Jeong, Ki-Seok,Jyung, Tae-Young,Baek, Young-Sik The Korean Institute of Electrical Engineers 2011 The Journal of International Council on Electrical Vol.1 No.2

This paper presents theoretical analysis based on mathematical model of Static Synchronous Compensator (STATCOM). The basic application of STATCOM is to supply voltage support to the power system. That is, the STATCOM can rapidly supply dynamic reactive power required for short-tem voltage regulation. However, through mathematical model of STATCOM using digital simulation, it is found that the system stability may tend to be unstable under some conditions due to some factors of STATCOM. The performances of STATCOM under specified load variation was simulated with EMTP (Electro Magnetic Transient Program)/RV. Simulation results are presented for a two-level VSC based ${\pm}100$ MVAR STATCOM connected to a 345 kV simple radial system. Simulation results validate the ability of the STATCOM to improve short-term voltage regulation. With appropriate PI gains, the controller performance is observed reasonably well during capacitive and inductive modes of operation. The simulation results from EMTP/RV represent good dynamic performances of STATCOM during step changes of load variation.

전력 품질 개선을 위한 STATCOM 시스템의 강인 안정도 해석

성화창(Hwa Chang Sung),박진배(Jin Bae Park),탁명환(Myung Hwan Tak),주영훈(Young Hoon Joo) 한국지능시스템학회 2010 한국지능시스템학회논문지 Vol.20 No.2

본 논문에서는 전력 품질 개선 및 전력 계통 신뢰도 향상을 위한 방안으로서 STATCOM 발전 시스템의 시스템 모델링 및 강인 안정성에 대한 연구를 수행하고자 한다. STATCOM은 복잡한 전력 계통을 안정화하고 공급전원을 일정하게 유지할 목적으로 제안된 기술이다. 기존의 전력 보상 장치에 비해 전력 제어 범위가 상당히 넓은 편이며, 시스템 구성요소가 비선형적 움직임을 보이고 있다. 또한, 외부 환경에 따른 파라미터 변동이 있기 때문에 시스템 제어를 위한 새로운 기법 마련이 필요하다. 이를 해결하기 위하여, 시스템을 퍼지 이론을 통해 접근하여 모델링을 수행하게 되며, 강인 안정도 해석을 통해 시스템의 불확실성 요소에 대한 대비를 하게 된다. This paper deals with the robust stability analysis of STATCOM (Static Synchronous Compensator) power system for power quality enhancement and power system stability. The STATCOM plays an important role in controlling the reactive power flow to the power network and hence the system voltage fluctuations and stability. The control areas of this plant are very large and the overall composition of the system is nonlinear. Also, STATCOM is influence of the uncertainties so that it is necessary to apply the new control technique. For solving these problems, we perform the fuzzy modeling and robust analysis for STATCOM system.

Analysis and Design of the Interface Inductor and the DC Side Capacitor in a STATCOM with Phase and Amplitude Control Considering the Stability of the System

Guopeng Zhao,Minxiao Han,Jinjun Liu 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.1

Previous publications regarding the design and specifications of the interface inductor and the DC side capacitor for a STATCOM usually deal with the interface inductor and the DC side capacitor only. They seldom pay attention to the influences of the interface inductor and capacitor on the performance of a STATCOM system. In this paper a detailed analysis of influence of the interface inductor and the DC side capacitor on a STATCOM system and the corresponding design considerations is presented. Phase and amplitude control is considered as the control strategy for the STATCOM. First, a model of a STATCOM system is carried out. Second, through frequency domain methods, such as transfer functions and Bode plots, the influence of the interface inductor and the DC side capacitor on the stability and filtering characteristics of the STATCOM are extensively investigated. Third, according to this analysis, the design considerations based on the phase margin for the interface inductor and the DC side capacitor are discussed, which leads to parameters that are different from those of the traditional design.

Modeling and State Feedback Controller for Current Source Inverter Based STATCOM

A. Ajami,M.Younesi 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

The static synchronous compensator (STATCOM) is increasingly popular in power system application. In general, power factor and stability of the utility system can be improved by STATCOM. Specifically, STATCOM can regulate the voltage of connection point and compensate the power factors of equipment serviced by that node. The dynamic performance of STATCOM is critical to these performance and stability function. STATCOM is a multi input and multi output system (MIMO), which can be presented by a mathematic model. In this paper, an optimal linear quadratic regulator (LQR) design is presented for transient dynamic performance of current-source converter based STATCOM.

전력품질 향상을 위한 배전용 STATCOM 운전결과 분석

오관일,전영수,박상태,추진부 전력전자학회 2000 전력전자학회 논문지 Vol.5 No.4

본 논문에서는 국내 최초로 설치된 Custom Power기기인 배전용 STATCOM(STATic COMpensator)의 기기 신뢰성 확보를 위힌 기가 테스트 및 설계통 운전 분석결과를 보이고 있다. Custom Power는 유연송전시스템(FACTS : Flexible AC Transmission System)과 같이 교류전력계통을 제어함으로써 효율적이고 유연한 전력계통의 운용과 구성을 목적으로 한다. STATCOM은 Custom Power기기의 한 형태로 무효전력 보상, 전압조정, 그리고 전압 퓰리커 억제 등의 기능을 가진다. 본 논문에서는 STATCOM 시운전 결과 무효전력과 역률 보상에서 우수한 성능을 보임을 확인할 수 있다. This paper presents the test and operation results of the domestic demonstration of the reactive power compensation device called STATCOM (STATic COMpensator). The object of the paper is to describe the reliability of the unit based on the extensive operation databases. The custom power is similar in nature to the concept of FACTS(Flexibel AC Transmission System). By controlling reactive power, the technology offers utilities the opportunity for increased efficiency and their capabilities will permit transmission planners make the best use of their existing transmission resources. STATCOM is a custom power device in a way and can be used in a similar way for the dynamic compensation of power transmission systems, providing reactive power compensation, voltage regulation and mitigation of voltage flicker. It is shown that the STATCOM has clear advantages in areas such as; providing reactive power compensation and improving power factor.

이중접속방식의 멀티스텝 인버터를 이용한 대용량 STATCOM의 개발

김태훈,배영상,최세완,이왕하 전력전자학회 2004 전력전자학회 논문지 Vol.9 No.1

In this paper a large scale STATCOM using double-connected multi-step inverter is proposed and operating principle along with control method is detailed. A simple auxiliary circuit including an interphase transformer is employed to improve output voltage waveform of 12-step into 36-step. The proposed scheme could be a cost effective approach in high power applications such as 10MVar to 30MVar STATCOM. Experimental results from a 2KVA laboratory prototype show validity of the proposed method. 본 논문에서는 이중접속 방식의 멀티스텝 인버터를 이용한 대용량 STATCOM에 관하여 동작원리 및 제어 방식을 기술하기로 한다. 기존의 12-스텝 인버터에 상간 변압기 및 간단한 보조회로를 이용하여 출력전압의 파형을 36-스텝으로 개선하였다. 이러한 방식의 인버터는 특히 10Mvar~30Mvar급 전후의 STATCOM에 적용하면 경제적이다. 2KVA급 STATCOM 시작품의 실험결과로부터 제안한 방식의 타당성을 입증하였다.

Current Limit Strategy of Voltage Controller of Delta-Connected H-Bridge STATCOM under Unbalanced Voltage Drop

Gum Tae Son,Jung-Wook Park 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

This paper presents the current limit strategy of voltage controller of delta-connected Hbridge static synchronous compensator (STATCOM) under an unbalanced voltage fault event. When phase to ground fault happens, the feasibility to heighten the magnitude of sagging phase voltage is considered by using symmetric transformation method in delta-structure STATCOM. And the efficiency to cover the maximum physical current limit of switching device is considered by using vector analysis method that calculate the zero sequence current for balancing the cluster energy in delta connected H-bridge STATCOM. The result is simple and obvious. Only positive sequence current has to be used to support the unbalanced voltage sag. Although the relationship between combination of the negative sequence voltage with current and zero sequence current is nonlinear, the more negative sequence current is supplying, the larger zero sequence current is required. From the full-model STATCOM system simulation, zero sequence current demand is identified according to a ratio of positive and negative sequence compensating current. When only positive sequence current support voltage sag, the least zero sequence current is needed.

STATCOM을 이용한 풍력단지가 연계된 전력계통의 과도안정도 향상

서규석(Seo, Gyu-Seok),박지호(Park, Ji-Ho) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.6

풍력단지가 연계된 전력계통의 과도안정도를 보장하기 위해서는 전력계통과 풍력단지의 접속점에 풍력발전기가 충 분한 무효전력을 공급할 수 있어야 한다. 하지만 개별의 풍력터빈은 안정도를 유지하기 위한 충분한 무효전력 공급능력을 가지지 못한다. 또한 풍력단지와 접속점 사이의 케이블은 리액턴스가 크고 이에 따른 무효전력 손실도 크다. STATCOM(Static Synchronous Compensator)은 고속으로 동작할 수 있고 충분한 무효전력을 공급할 능력을 가지고 있기 때문 에 과도안정도를 향상시킬 수 있다. 본 논문에서는 풍력단지가 연계된 전력계통의 과도안정도 향상에 있어서 STATCOM의 유효성을 보인다. 접속점에 STATCOM을 설치하고 동적 모의를 한 결과 과도 안정도가 향상되는 결과를 얻을 수 있었다. To ensure the transient stability of power system connected to a wind farm, wind power plant must be able to supply reactive power at the point of the common coupling(PCC). The reactive power capability of each individual wind turbine may not sufficient to maintain stability. Also, there are large reactive power losses in connection cables between wind farm and PCC. The static synchronous compensator(STATCOM) is considered for transient stability enhancement, because it provides many advantages such as the fast response time and superior reactive power support capability. In this paper, the effectiveness of a STATCOM in enhancing transient stability of power system connected to a wind farm is presented. The results of dynamic simulations show that STATCOM installed at the PCC can enhance transient stability.

Chopper Controller Based DC Voltage Control Strategy for Cascaded Multilevel STATCOM

Lian-Song Xiong,Fang Zhuo 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.2

The superiority of CMI (Cascaded Multilevel Inverter) is unparalleled in high power and high voltage STATCOM (Static Synchronous Compensator). However, the parameters and operating conditions of each individual power unit composing the cascaded STATCOM differ from unit to unit, causing unit voltage disequilibrium on the DC side. This phenomenon seriously impairs the operation performance of STATCOM, and thus maintaining the DC voltage balance and stability becomes critical for cascaded STATCOM. This paper analyzes the case of voltage disequilibrium, combines the operation characteristics of the cascaded STATCOM, and proposes a new DC voltage control scheme with the advantages of good control performance and stability. This hierarchical control method uses software to achieve the total active power control and also uses chopper controllers to enable that the imbalance power can flow among the capacitors in order to keep DC capacitor voltages balance. The operating principle of the chopper controllers is analyzed and the implementation is presented. The major advantages of the proposed control strategy are that the number of PI regulators has been decreased remarkably and accordingly the blindness of system design and debugging also reduces obviously. The simulation reveals that the proposed control scheme can achieve the satisfactory control goals.