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In order to solve the problems caused by the pulsating current ripple of switching-mode power converters, a passive pulsating ripple canceling circuit (PPRCC) is proposed in this paper. The features of the proposed PPRCC include simple, modular structure, and high degree of design flexibility. By integrating the proposed PPRCC, an input current ripple-free flyback-type converter is adopted and analyzed as an example because of its comprehensive utilization in small power rating commercial products. In addition, the switch voltage spike of flyback converter can be suppressed by integrating the proposed PPRCC without using snubbers, it turns out that the efficiency can be further improved. The corresponding operating principle, steady-state analysis, and zero ripple design criteria of the proposed PPRCC are provided. Finally, a 100 W laboratory prototype is constructed to verify the effectiveness of the proposed principle. Experimental results show that the resulting peak-to-peak input current ripple is reduced by 96% and nearly 0.5% and 1.7% improvement in efficiency can be achieved by the proposed PPRCC, at 80 W and 100 W load conditions, respectively.

A bidirectional DC-DC converter with a wide- range voltage conversion ratio is proposed in this paper. The characteristic of wide-range voltage conversion ratio can be utilized in the energy conversion of retired batteries, such as electric scooters, electric vehicles, electrical buses, electric trucks etc. with different voltage levels. The proposed converter is composed of cascading a two-phase interleaved half-bridge circuit and a voltage-doubler circuit. The two-phase interleaved half-bridge circuit and the voltage-doubler circuit are defined as terminals A and B, respectively to investigate the operational stages of the proposed converter and analyze the voltage conversion ratios under different voltage-level schemes. Due to the variable structure design and control of the proposed converter, a wide-range voltage converter ratio and bidirectional step-up/step-down function can be achieved. A prototype for the proposed bidirectional DC-DC converter with a rated voltage of 150V at terminal A, a rated voltage between 25V and 1050V at terminal B and a rated power of 1100W is designed and implemented in this paper. Experimental results demonstrate that the proposed bidirectional DC-DC converter can be operated in the different modes with respect to different voltage levels. Meanwhile, the maximum conversion efficiency of above 98% can be achieved.

Fault Management System (FMS) is one of the main functions in Distribution Automation System (DAS); however, the conventional FMS cannot be used in distribution systems with Distributed Generators (DGs) due to the lack of directional function. The directional fault detection device is expensive due to the expensive directional module used. In a wide-ranging distribution system, the investment cost will be very high if the fault detecting devices are expensive. Therefore, the design and implementation of a cost-effective FMS for distribution system with DGs is necessary. A Multi-Level Fault-Current Indicator (MLFCI) having a plurality of reed switches used to detect different current levels is proposed in this paper. The hardware prototype is designed and implemented. An algorithm used to locate fault based on the different fault current levels is derived. A MLFCI-based FMS for distribution systems with DGs is then realized. Experimental results demonstrate the feasibility of the proposed MLFCI. Simulation results are then used to demonstrate the validity of the proposed MLFCI-based FMS for distribution systems with DGs.

Fault indicating devices such as fault indicators (FIs) have been widely used in distribution systems to improve reliability and reduce outage duration. Recently, FIs with communication interfaces are integrated into distribution automation (DA) to further reduce fault-finding time by reporting FIs' statuses back to control center. When faults occur, a lot of alarms and fault information are received from Outage Management System (OMS), Trouble Call System (TCS) and Customer Information System (CIS) and are shown to system operators. As a result, the identification of faulted line sections in a wide-ranging distribution system from FIs' statuses is not an easy task, especially when multiple faults occur simultaneously and/or distributed generators (DGs) are connected. An automatic and fast faulted line-section location method for distribution systems based on FIs is proposed in this paper. The line sections between adjacent FIs can be treated as a possible fault location (PFL) and the fault current detected by the FI can be considered as line current (LC) flowing between the adjacent PFLs. A relationship matrix between PFLs and LCs is then derived and used to design the proposed automatic and fast faulted line-section location method. The faulted line sections can then be located effectively and efficiently by the proposed method. Test results for an actual distribution system demonstrate the validity of the proposed faulted line-section location method.

Utilizing battery storage systems (BSSs) can reduce the intermittent output of PV generation systems (PVGSs) and make them dispatchable. The aim of this paper is to design an optimal charging/discharging scheduling for BSSs such that the line loss of distribution systems interconnected with sizeable PVGSs can be minimized. A mathematical model for BSSs which can be used to simulate the charging procedures such as the commonly-used constant current to constant voltage (CC-CV) charging method, the discharging procedures and the state of charge (SOC) is proposed first. The minimum line loss problem considering the intermittent output of PVGSs and the scheduling of BSSs is then formulated based on the BSS mathematical model. The optimal charging/discharging scheduling of BSSs can then be obtained by a genetic algorithm (GA) based method. Test results demonstrate the validity of the proposed mathematical model and optimal charging/discharging scheduling for BSSs.

Radio frequency identification (RFID) is looked upon as one of the top ten important technologies of the twentieth century. In coming years, public area applications are the key issue in developing RFID. Power systems are innately bulky, large, and definitely, an extremely important application area for RFID. In power areas, RFID has great potential to be applied extensively to customers. Therefore, an RFID-based power meter and outage recording system is proposed in this article. The proposed system can be used to fully collect and record power consumption data and power reliability information on customers. A small-scale power meter and outage recorder is designed first and then an RFID system is designed and embedded into the power meter and employed to record the power data in tags. A handheld meter management system is also designed in this article to collect the data stored in the tags and synchronize the collected data with rear-end processing if necessary. Due to the uniqueness of RFID tags, the p...

Fault Current Indicators (FCIs) with communication interfaces have been widely used in distribution systems to reduce fault-finding time. The effectiveness of a Fault Management System (FMS) composed of FCIs greatly depends on the performance of the communication network deployed by the FCIs and the failure rates of distribution systems. The conventional techniques only focus on the issues of optimal number and location of FCIs or communication network deployment individually, therefore, the effectiveness of an FMS cannot be assessed realistically. A systematic effectiveness assessment methodology for FMS considering the performance of the communication network deployed by the FCIs and the failure rates of distribution systems is vital and is investigated in this paper. A communication evaluation platform is designed in this paper and used to acquire the field measurements of communication parameters. The communication parameters, especially the Packet Success Rate (PSR), between two adjacent FCIs are measured, and the Probability Density Function (PDF) of the PSR can be built accordingly. The effectiveness of the FMS is then assessed by stochastic analysis considering the failure rates of the distribution system and PSR PDFs between two adjacent FCIs. Due to the characteristics of easy installation, maintenance, longer battery life, lower cost, and so on of ZigBee, the ZigBee-based FCI is mainly discussed in this paper. In order to efficiently find the communication route when a fault occurs, a fast communication route tracking method is also proposed in this paper and its feasibility is demonstrated in an actual distribution system. Experimental and simulation results demonstrate the validity of the proposed systematic effectiveness assessment methodology for an FMS composed of FCIs. The proposed assessment methodology can more realistically react to the actual conditions of the FMS and therefore save on installation time and costs.

This paper studies the wireless ZigBee network deployment for distribution feeders, especially, for the intelligent fault indicators mounted on distribution feeders. Researches reveal that ZigBee is suitable for constructing the communication network within distribution automation and/or smart grids; however, the network deployment should be carefully evaluated to make sure that the communication quality, packet error rate for example, is acceptable. Therefore, communication quality evaluation software for ZigBee network deployment which makes use of Google map is designed in this paper. The proposed software can be used to select the candidate locations for intelligent fault indicators placement by inspecting the terrain and possible obstacles from Google map and then the actual field test can be conducted. Different test scenarios including urban feeders, suburban feeders and mountainous feeders with respect to different transmitting range and obstacles can be conducted in the proposed software. The ZigBee network deployment procedure for distribution feeder is also recommended. Experimental results demonstrate the validity of the proposed system.

A charging/discharging monitoring and simulation platform for Li-ion batteries is designed and implemented in this paper. Most of chargers are designed based on the rated voltage and/or current of batteries without taking the battery parameters and energy sources of chargers into account. For example, the utilization of renewable energies such as Photovoltaic (PV) as the energy source of the charger has been treated as a new energy option recently. However, due to the unstable energy characteristic of PV, more analysis and investigation should be conducted for the design of PV-based charger. Therefore, a well designed charging/discharging monitoring and simulation platform that can take unstable energy characteristic and battery parameters' variation into account and help the charger deigns is desirable. The proposed platform can be used to monitor the voltage and current in the charging/discharging process, to calculate the circuit parameters of battery model and to simulate the charging/discharging process. A PV-based charger for Li-ion batteries is implemented in this paper and some experiments and simulations for the designed charger are conducted. Experimental results that agree well with simulated results demonstrate the validity of the proposed platform.

The paper develops and implements a novel fault indicator for distribution automation to achieve significant and immediate improvement in reliability and hence service to the electricity customers. The proposed fault indicator is designed based on ZigBee communication. ZigBee has been designed to possess general-purpose protocol with low cost, low power consumption and self networking; and therefore, it is very suitable for constructing the communication network in distribution automation and therefore smart grids in the future. A fault detection and identification system is also designed to find out the fault location effectively and efficiently after a fault occurred. Experimental results demonstrate the validity of the proposed system.

The installation of Advanced Metering Infrastructure (AMI) is looked upon as a bridge to the construction of smart grids; especially, while most of the power meters are still mechanical ones without digitization. An AMI consists of smart power meter, communication technology, meter data management, and associated software and hardware. After AMI has been implemented, many advanced functions e.g. automatic and accurate reliability calculation systems can be achieved. Therefore, this paper tries to develop an automatic reliability system for AMI. A ZigBee-based smart power meter with outage recording function is designed first. The ZigBee-based power meters are used to transmit the detailed power consumption data and outage event data to rear-end processing system periodically. According to the detailed and accurate data stored in the rear-end database, an automatic and accurate reliability calculation system can be designed sequentially. The customer interruption costs can also be estimated by the proposed system. Experimental results show that the proposed system has great potential to be integrated into AMI to improve the accuracy of reliability calculation.

Radio Frequency Identification (RFID) system is looked upon as one of the top ten important technologies in the 20th century. Industrial automation application is one of the key issues in developing RFID. Therefore, this paper designs and implements a RFID-based autonomous mobile car for more extensively application of RFID systems. The microcontroller of Microchip PIC18F4550 is used to control the autonomous mobile car and to communicate with RFID reader. By storing the moving control commands such as turn right, turn left, speed up and speed down etc. into the RFID tags beforehand and sticking the tags on the tracks, the autonomous mobile car can then read the moving control commands from the tags and accomplish the proper actions. Due to the convenience and non-contact characteristic of RFID systems, the proposed mobile car has great potential to be used for industrial automation, goods transportation, data transmission, and unmanned medical nursing etc. in the future. Experimental results demonstrate the validity of the proposed mobile car.

Many governments deploy ubiquitous IT project, which aims to combine the latest wireless network and wide-band technologies etc. to accomplish a ubiquitous wireless communication network. The ubiquitous wireless communication network can be utilized for the Advanced Metering Infrastructure (AMI). Therefore, this paper tries to use the new wireless communication technologies to design and implement a ZigBee-based smart power meter. An outage recording system is also designed and embedded into the smart meter. The microcontroller of Microchip dsPIC30F series is used to develop the proposed smart power meter. A ZigBee system is then deigned and integrated into the proposed power meter, and used to transmit the detailed power consumption data and outage event data to rear-end processing system. The proposed smart power meter cannot only be used for power consumption data collection but also for outage event data recording. The proposed system has great potential to be used to build the area-based AMI. Experimental results demonstrate the validity of the proposed system. Besides, the application of ZigBee communication in power area may, expectedly, lead to make a definite contribution to ubiquitous IT project.

Radio frequency identification (RFID) system is looked upon as one of the top ten important technologies in the 20th century. In the upcoming years, the public area applications are the key issue in developing RFID. Power system is innately bulky, wide-spreading, and is, definitely, an extremely important application area of RFID. In the power area, the RFID can be implemented on apparatus management, procedure control, power consumption management and personnel access control. Additionally, RFID can be applied extensively to customers. By integrating RFID into a power meter and outage recorder, the power consumption data and power reliability information of customers can be fully collected and recorded. This paper tries to design and implement a RFID-based power meter and outage recording system. The microcontroller of Microchip dsPIC30F series is used to develop a small-scale power meter and outage recorder. The proposed RFID system is then embedded into the power meter and records the power data in tag. Due to the uniqueness of RFID tag, the power consumption data and outage information of customers can all be recorded and then be identified in the rear-end processing system. Experimental results show the validity of the proposed system.