Automatic Load Transfer Research Articles

Evaluation of operational reliability in an electrical distribution feeder

This work analyzes the options for repowering, reconfiguration, and automatic load transfer that a feeder can have. The study was carried out from the head of a distribution substation using the CYMDIST application, through which the failure rate, repair time, and availability and unavailability indices were determined. Using the "Reliability Analysis" module of the CYMDIST software, consumer-oriented reliability indices are obtained, allowing a reconfiguration and the optimal path to be identified in a reasonable analysis time. The main results show that the repair time should be shorter than the maneuvering time for reconnection. It was also possible to define the conditions for ensuring proper operation before and after the fault, the location of the automatic reconnection equipment, and the communication system used.

Control and Protection of Medium Voltage Distribution Network Based on Unified Power Flow Controller

The integration of diverse load types, such as large-scale distributed generators and charging stations, presents considerable challenges to distribution networks. The Unified Power Flow Controller (UPFC) provides multiple benefits, including its compact dimensions, cost efficiency, seamless regulation, and swift response. When deployed in distribution networks, the UPFC facilitates the creation of a Distribution Unified Power Flow Controller (DUPFC) system. The DUPFC system enhances medium voltage distribution network regulation but also affects power quality, fault characteristics, and relay protection accuracy. To address these issues, a power flow equivalent circuit model for the medium voltage distribution loop network was developed. The operating principle and steady-state model of the UPFC were investigated, based on distribution loop network parameters and power flow distribution characteristics. A UPFC control strategy was designed to create a suitable DUPFC system for the medium voltage distribution loop network, ensuring coordination between UPFC protection and the distribution system’s protection mechanisms. This system accomplishes rapid fault isolation and automatic load transfer. Finally, a simulation model based on a typical 20 kV distribution loop network structure was selected to validate the effectiveness of the UPFC control strategy and the DUPFC protection system in MATLAB/Simulink.

Integration of Home Automation and Security System Controller with FPGA Implementation

A home automation system is essential for promoting a safe and comfortable living environment and notable energy conservation for the user. However, the system’s favour had been obstructed by cost, power usage, inadequate security, complexity, and no emergency backup power. Current home automation systems with controllers were limited by their number of ports, fixed architecture, non-durable and non-parallel executions. Keeping this in view, integration of home comfort system, security system, and the automatic load transfer switch features are proposed using the base of Cyclone IV E: EP4CE115F29C7 FPGA Board (DE2-115). The top-level module is developed via Verilog Hardware Descriptive Language (HDL) with the bottom-up technique and used test bench for functional verification via ModelSim-Altera. The PWM method was applied to the lighting system to control the dimming of light through its digital signals via a maximum 500000 counter to improve energy efficiency for the proposed design. In this project, 200Hz pulses are successfully simulated to prevent visible flickering of lights in duty cycle generation. The light intensity of 40% and 100% are verified and successfully generated according to the inputs provided by the status of the LDR sensor and IR sensor. The proposed controller gives correct corresponding outputs to the 13 actuators based on the detected input stimuli. The proposed design utilized a total of 162 (<1%) logic elements, 32 registers, and total pins of 74 (14%). The proposed design successfully integrated the three-sub module and provided control on comfort and security system operations to prevent service failure during power blackout conditions at the top-level and utilized a low ratio of the FPGA.

Restoring normal network operation mode by automatically disabling network ATS

Automatic sectionalizing and redundancy of power transmission lines is one of the conditions for network intellectualization and can significantly reduce the power supply interruption time for rural consumers. However, both sectionalizing and redundancy of power transmission lines in 0.4 kV electric networks are used extremely limitedly since there are no sufficiently effective methods and technical means for their implementation. This article presents a method to automatically deactivate the automatic load transfer switch when restoring the normal network operation mode. The paper considers the implementation of the method on the example of damage occurring in the network where power is supplied to consumers from two power sources using an automatic load transfer switch and two sectionalizing units. A device is developed which allows implementing the developed method of automatic load transfer switch deactivation. The device consists of sectionalizing unit, automatic load transfer switch, voltage presence sensor, power direction sensor, memory element, repeater element, element AND and 3 elements NOT. The work of the device is described. The proposed method for automatically disconnecting the automatic load transfer switch in order to return the consumers’ power supply circuit to its initial state solves the problem of eliminating unreasonable power supply interruptions for consumers.

Sectionalizing and Redundancy of the 0.38 kV Ring Electrical Network

The use of power line sectionalizing and power line redundancy in 0.38 kV networks entails the need to take into account the fact that currents and voltages can vary significantly at different points of the network. The article proposes a mathematical model to solve this problem. The mathematical model is based on the method of phase coordinates. Using mathematical modeling, the article determines the voltages and currents in the sections of the backup line after the automatic load transfer switch is activated. The article also proposes an improvement in the scheme of the power line sectionalizing unit. The sectionalizing unit scheme is suggested to be modified with a bypass circuit and the installation of a voltage indicator for signaling the voltage presence on the lower contacts of the switch.

Choice of commutation device and development of the scheme of a universal sectionalizing point with automatic load transfer function for the 0.38 kV electric network

The overestimated length of rural power lines of 0.38 kV leads to the fact that it is often not possible to fulfill both the sensitivity conditions of the protective device installed at the transformer substation and protecting the line from overloads and short circuits, and the requirements of the power supply reliability of consumers. This problem can be solved by installing in-line universal sectionalizing point equipped with an automatic load transfer function. The use of these devices allows dividing a line into sections provides the necessary sensitivity of protection for each section of the line and the possibility of supplying power to undamaged areas from a backup power source. In addition, only with the use of automated switching devices installed in power lines, it is possible to create intelligent electrical networks. When developing these devices, it is necessary to take into account the electromechanical characteristics of switching devices that are planned to be used for switching lines.

Distribution network reconfiguration validation with uncertain loads – network configuration determination and application

Automatic load transfer (ALT) on the 11 kV network is the process by which circuit breakers on the network are switched to form open points in order to feed load from different primary substations. Some of the potential benefits that may be gained from dynamically using ALT include maximising utilisation of existing assets, voltage regulation and reduced losses. One of the key issues, that has yet to be properly addressed in published research, is how to validate that the modelled benefits really exist. On an 11 kV distribution network where the load is continually changing and the load on each distribution substation is unlikely to be monitored - reduction in losses from moving the normally open point is particularly difficult to prove. This study proposes a method to overcome this problem and uses measured primary feeder data from two parts of the Western Power Distribution 11 kV Network under different configurations. The process of choosing the different configurations is based on a heuristic modelling method of locating minimum voltages to help reduce losses.

Loads and Stress Analysis Cycle Automation in the Automotive Suspension Development Process

The article describes the use of the Multi-Body Dynamics (MBD) models, the Finite Element Analysis (FEA) and the CAD-modelling process in the automotive suspension development. Automation of maximum quasi-static loads calculation with the automatic two-way geometry update between MBD/CAD-models and automatic load transfer to the finite element analysis allows performing numerous analysis of suspension during development without significant time consumption, and, hence, provides an increased accuracy and reliability of stress analysis results.

직접연계방법에 의한 DAS-SCADA 연계 연구

배전자동화시스템(DAS:Distribution Automation System)과 변전자동화시스템(SCADA:Supervisory Control And Data Acquisition)은 전력계통을 컴퓨터와 통신기술을 이용하여 운용하는 주된 시스템으로, 현재 독립적으로 운영됨으로 인해 신속하게 처리되어야 하는 고장처리 및 활선작업처리가 지연되는 등의 문제점이 제기되어왔고, 이에 따라 DAS-SCADA 연계 연구가 요구되었다. 연계방법으로 직접연계, 웹연계, DAS 기능부 전력량계를 이용한 연계가 2005년 11월부터 2007년 12월까지 한전 사업소에서 시범 운영되었고, 그 결과 투자비용 면에서 직접연계방법이 웹연계 방법에 비해 약 1.3배 높지만 다양한 변전소 운전정보 전달의 신속성, 제어기능 우수 등의 타당성이 입증됨으로써 직접연계방법에 의한 DAS-SCADA 연계가 2010년까지 한전 사업소에 전국적으로 확대 적용될 계획이다. 시범 운영시 제기된 문제점을 개선하기 위해 변전소 개체별 통신 방법을 이용한 데이터 연계방안으로 개선하여 연계DB 자동구축 기능 및 연계시스템 진단/Log 기능을 개발하였다. 연계데이터 포인트와 통신데이터 종류를 정의하고, SCADA HMI 프로그램을 개발하여 변전소 단선도 자동생성 기능, 변전소 단선도 수동편집 기능, SCADA 감시 제어기능 및 이력관리 기능을 개발하였다. DAS-SCADA 연계시 정전건당 평균시간을 약 33% 단축하여 전력공급 신뢰도를 향상하고, 배전 계통운영센터와 변전소간 활선작업 처리절차 축소로 전력계통 효율적 운영에 기여하고, 나아가 고장시 부하절체 자동처리로 완전한 배전자동화 실현 및 해외 수출화 사업에도 크게 기여할 것으로 기대된다. DAS and SCADA system are main systems, which operate and manage the power system by using computer and communication technology. But DAS and SCADA have been operated independently in Korea, so there was some time delay in the fault handling and live-line work. To improve that problems, studies on the interface between DAS and SCADA have been needed. From November 2005 to December 2007, the pilot project has been performed in KEPCO's branch offices, as a result, direct method will be applied widely all over the country until 2010 because the operation information of substation users want can be transmitted fast and it is possible to control 43RC directly although the expense for direct method is about 1.3 times larger than that for web method. To improve problems revealed during the pilot project, substation object to object communication method is proposed and interface database automatic generation and interface system diagnosis and logging functions are developed. Interface data point and communication data type are defined, substation single line diagram automatic generation or manual editing function, SCADA monitoring and controlling function, log data managing function are developed in SCADA HMI program. It is expecting to reduce the average time for each outage about 33% and to improve the reliability, efficiency of operation, execution of DAS from automatic load transfer under a fault, and to contribute to export project.

Automatic Crane Load Transfer System for Offshore Operation

Automatic Crane Load Transfer System for Offshore Operation