Feeder Remote Terminal Unit Research Articles

배전지능화 단말장치의 모의시험을 위한 가상 배전계통 HILS 시스템 개발

This paper proposes a virtual distribution HILS(Hardware-In-the-Loop Simulation) system for testing of FRTU(Feeder Remote Terminal Unit) for distribution automation systems. Recently, the distribution automation systems have been complicated because of the reliability improvement of the power system, new power distribution facilities, and upgrading the operating system. However, real-time digital simulators are difficult to build systems due to expensive facilities and cannot implement actual distribution automation systems. Therefore, in this paper, the HILS system is developed by using FRTU, interface devices based on DSP(Digital Signal Processor), Labview monitoring through the TCP/IP communication, and real-time power system analysis simulator. The proposed HILS system is verified through the results of systematic analysis of distribution automation systems, real-time simulation, and functional verification by using the feeder remote terminal unit.

A Dynamic Programming Algorithm for Leveraging Probabilistic Detection of Energy Theft in Smart Home

In the modern smart home and community, smart meters have been massively deployed for the replacement of traditional analog meters. Although it significantly reduces the cost of data collection as the meter readings are wireless transmitted, a smart meter is not tamper-resistant. As a consequence, the smart grid infrastructure is under threat of energy theft, by means of attacking a smart meter so that it undercounts the electricity usage. Deployment of feeder remote terminal unit (FRTU) helps narrow the search zone of energy theft in smart home and community. However, due to budgetary limit, utility companies can only afford to insert the minimum number of FRTUs. This imposes a signifcant challenge to deploy the minimum number of FRTUs while each smart meter is still effectively monitored. To the best of our knowledge, the only work addressing this problem is [1] , which uses stochastic optimization methods. Their algorithm is not very practical as it cannot handle large distribution networks because of the scalability issue. Due to the inherent heuristic and non-deterministic nature, there is no guarantee on the solution quality as well. Thus, the high performance energy theft detection is still needed for this energy theft problem. In order to resolve this challenge, we propose a new dynamic programming algorithm that inserts the minimum number of FRTUs satisfying the detection rate constraint. It evaluates every candidate solution in a bottom-up fashion using an innovative pruning technique. As a deterministic polynomial time algorithm, it is able to handle large distribution networks. In contrast to [1] which can only handle small system, our technique can perform FRTU insertion for a large scale power system. Our experimental results demonstrate that the average number of FRTUs required is only 26% of the number of smart meters in the community. Compared with the previous work, the number of FRTUs is reduced by 18.8% while the solution quality in terms of anomaly coverage index metric is still improved.

Strategic FRTU Deployment Considering Cybersecurity in Secondary Distribution Network

This paper is concerned about strategic deployment of feeder remote terminal unit (FRTU) in primary network by considering cybersecurity of distribution secondary network. First, detection of historical anomaly load profile in secondary network is assumed to be observable. These irregularities of historical energy usages can be determined from consumer billing centers using proposed cybersecurity metrics. While it is constrained by budget on the number of FRTUs that can be deployed, the proposed algorithm identifies pivotal locations of a distribution feeder to install the FRTUs in different time horizons. The simulation results show that the infrastructure enhancement using proposed multistage method improves investment planning for distribution systems.

CIM 기반의 배전자동화 시뮬레이터

The main purpose of the distribution automation system (DAS) is to achieve efficient operation of primary distribution systems by monitoring and control of the feeder remote terminal unit(FRTU) deployed on the distribution feeders. DAS simulators are introduced to verify the functions of the application software installed in the central control unit(CCU) of the DAS. Because each DAS is developed on the basis of its own specific data model, the power system data cannot be easily transferred from the DAS to the simulator or vice versa. This paper presents a common information model(CIM)-based DAS simulator to achieve interoperability between the simulator and the DASs developed by different vendors. The CIM-based data model conversion between Smart DMS (SDMS) and Total DAS (TDAS) has been performed to establish feasibility of the proposed scheme.

SCADA 기능과 전기품질 온라인 감시 및 배전설비 열화감시 기능을 갖는 배전지능화 시스템 개발

Intelligent distribution automation system have total monitoring and control capability. The system covers substation, distribution network, distributed generations and customers at HV system. Various intelligent distribution facilities installed at distribution systems have voltage sensor, current sensor, aging monitoring sensor. Intelligent Feeder Remote Terminal Unit (IFRTU) tied to intelligent distribution facilities process information from facilities and it checks information of fault, power quality and aging of distribution facilities. The information is transmitted to master station through communication line. The master station have remote monitoring system covers substation, distribution network, distributed generations and customers. It also have various application programs that maintain optimal network operation by using information from on-site devices.

The FRTU-Based Fault-Zone Isolation Method in the Distribution Systems

In this paper, an intelligent feeder remote terminal unit (FRTU)-based operation and control strategy is proposed, which can improve the accuracy and quickness of the fault-zone determination and isolation from such problems as general fault, high impedance fault (HIF) and in-rush current (IRC) in the distribution system, including overhead and underground feeders. In the proposed method, each FRTU inferring the fault or inrush current determines whether its feeder is a fault or not, and whether its sink zone is a fault zone or not, by exchanging fault information (such as current value, voltage value, current direction) with the other FRTUs on the feeders under the ubiquitous-based distribution system that enables the FRTUs to be connected freely to the network. In order to explain the effectiveness of the proposed method, several cases are simulated for typical distribution using the developed simulator.

A Self-Isolation Method for the HIF Zone Under the Network-Based Distribution System

When a high-impedance fault (HIF) occurs in any zone of a distribution system, it is very difficult to detect the fault because the fault current is very small and the time of its occurrence cannot be ascertained. This paper proposes a self-isolation method for an HIF zone in which the feeder remote terminal unit (FRTU) experiencing nil-voltage can identify and isolate autonomously an HIF zone by exchanging voltage and current information with the neighbor FRTUs on the feeder when an HIF occurs under the network-based distribution system. Also, the method was devised to enhance the reliability of HIF identification from the voltage sensor error. Furthermore, new and simple heuristics are proposed, which are required to classify the nil-voltage due to an HIF with nil-voltage caused by general fault outage, scheduled outage, and outage due to the reclosing operation of a protective device (circuit breaker or recloser).

Ungrounded System Fault Section Detection Method by Comparison of Phase Angle of Zero-Sequence Current

In this paper, an integrated fault section detection and isolation strategy is proposed based on the application of the Distribution Automation System(DAS) utilizing advanced IT and communication technologies. The Feeder Remote Terminal Unit(FRTU) has been widely used to collect data in the Korean distribution system. The achieved data is adopted in this method for detecting multiple fault types. Especially in the case of single phase-to-ground fault, the fault section is detected by comparison of the zero-sequence current phase angle. The test results have verified the effectiveness of the proposed method in a radial distribution system through extensive simulations in Matlab/Simulink. Furthermore, a communication-based demo system identical to the simulation model has been developed, and it can be applied as an online monitoring and control program for fault section detection and isolation.

A Voltage Control Method based on Constants of Four Terminals Network Modeling of Distribution Networks

In this paper, a new algorithm of optimal voltage control is proposed for the Distribution Automation System (DAS) based on constants of four terminal network modeling. In the proposed method, the voltage profiles along feeders are estimated from the measurement of the current and power factor by a Feeder Remote Terminal Unit (FRTU) installed at each node. Whenever the voltage profile violates the restriction, the voltage control strategy is applied to keep the voltage levels along the feeders within the pre-specified range through the modification and coordination of the transformer under-load tap changers (ULTC), step voltage regulator (SVR), as well as shunt condenser. In the case studies, the estimation and control of the voltages have been testified in a radial distribution system with 11 nodes.

퍼지클러스터링 기법과 신경회로망을 이용한 고장표시기의 고장검출 능력 개선에 관한 연구

본 논문은 전력계통의 배전계통시스템에서 FRTU(Feeder remote terminal unit)의 고장검출 알고리즘의 개선에 관한 연구이다. FRTU는 상과 지락에 관한 고장검출을 할 수 있다. 특히 고장픽업 기능과 돌입억제기능은 일반적인 부하전류로부터 고장전류를 구별할 수 있다. FRTU는 돌입전류 또는 설정값을 초과한 고장전류가 발생하면 고장표시기(FI)로 고장을 발생한다. 짧은 시간 푸리에 변환(STFT) 분석은 주파수와 시간에 관한 정보론 제공하고, 퍼지 중심 평균 클러스터링(FCM) 알고리즘은 고조파의 특성을 추출한다. 고장 검출기의 신경회로망 시스템은 최급강하법을 이용하여 고장상태로부터 돌입전류를 구별하도록 학습된다. 본 논문에서는 FCM과 신경회로망을 이용하여 고장검출기법을 개선하였다. 검증에 사용된 데이터는 22.9KV 배전계통 시스템에서 실제 측정된 데이터이다. This paper focuses on the improvement of fault detection algorithm in FRTU(feeder remote terminal unit) on the feeder of distribution power system. FRTU is applied to fault detection schemes for phase fault and ground fault. Especially, cold load pickup and inrush restraint functions distinguish the fault current from the normal load current. FRTU shows FI(Fault Indicator) when the fault current is over pickup value or inrush current. STFT(Short Time Fourier Transform) analysis provides the frequency and time Information. FCM(Fuzzy C-Mean clustering) algorithm extracts characteristics of harmonics. The neural network system as a fault detector was trained to distinguish the inruih current from the fault status by a gradient descent method. In this paper, fault detection is improved by using FCM and neural network. The result data were measured in actual 22.9kV distribution power system.