A Wide Range and High Swing Charge Pump for Phase Locked Loop in Phasor Measurement Unit

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Phasor Measurement Units are widely utilized in power systems to provide synchrophasor data for a verity of applications, mainly performed by Energy Management Systems (EMS). Synchrophasors are measured at different parts of the network and transmitted to Phasor Data Concentrator (PDC) at a rate of 30-60 samples per second. The synchronization is done by means of a phase locked oscillator inside PMU which uses clock signal of the Global Positioning System (GPS). In this paper a novel charge pump with an appropriate operation capability in phaselocked-loops is presented. By using this phase locked loop in phasor measurement unit, the total performance of this circuit will be improved. The proposed charge pump uses current mirror techniques in order to achieve a wide range of output voltage to control the oscillator and also has a good performance in a wide frequency range from 33MHz to 555MHz. This circuit is designed and simulated in TSMC 0.18μm CMOS technology. The proposed charge pump only consumes 390μW power in supply voltage of 1.8V at 500MHz and has a maximum current of 16.43μA with an acceptable current matching between source and sink currents. It is also capable to be used in a wide frequency range and low power applications

Design of a 41.14-48.11 GHz triple frequency based VCO

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Growing deployment of more efficient communication systems serving electric power grids highlights the importance of designing more advanced intelligent electronic devices and communication-enabled measurement units. In this context, phasor measurement units (PMUs) are being widely deployed in power systems. A common block in almost all PMUs is a phase locked oscillator which uses a voltage controlled oscillator (VCO). In this paper, a triple frequency based voltage controlled oscillator is presented with low phase noise and robust start-up. The VCO consists of a detector, a comparator, and triple frequency. A VCO starts-up in class AB, then steadies oscillation in class C with low current oscillation. The frequency of the VCO, which is from 13.17 GHz to 16.03 GHz, shows that the frequency is tripling to 41.14-48.11 GHz. Therefore, its application is not limited to PMUs. This work has been simulated in a standard 0.18 µm CMOS process. The simulated VCO achieves a phase noise of -99.47 dBc/Hz at 1 MHz offset and -121.8 dBc/Hz at 10 MHz offset from the 48.11 GHz carrier

A Practical Integrated Fault Location Method for Electrical Power Distribution Networks

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Future distribution systems are expected to be self-healing systems which can manage the faults and quickly restore the customers from outage. As the basic function of fault management systems, fault location methods play an important role in reducing the outage time and related costs. This paper aims to present a practical method that provides precise and reliable estimations of the fault location. The method is an integration of a voltage sag-based method and an impedance-based method. Following to any permanent fault, the proposed method first uses the voltage sag magnitudes measured by a limited number of meters to find the closest node to the fault. Then, it investigates the lines connected to the node selected and uses an impedance-based method to find the exact fault location. The method proposed can be applied to large-scale distribution systems having several laterals and load taps. Simulations are on a practical distribution system are performed to test the method performance. The simulation study includes a comparative analysis with two other recent methods reported in the literature. The results show the better accuracy of the proposed method even with measurement inaccuracies and load data errors

Market power appearance through game theoretic maintenance scheduling of distributed generations

The oligopoly structure of the market and the network constraints may produce results far from the perfect competition. Maintenance decisions in an oligopolistic electricity market have a strategic function, because GENCOs usually have impacts on market prices through capacity outages. This paper describes generation maintenance planning in an oligopolistic environment as a strategic decision. In this paper a game theoretic framework is modeled to analyze strategic behaviors of GENCOs. Each GENCO tries to maximize its payoff by strategically making decisions, taking into account its rival GENCOs' decisions. Some GENCOs own DG units, such as wind, diesel, biomass and fuel cell plants. If different GENCOs find out they have the conditions of exerting market power exact in maintenance periods; they will share their data and they will cause some area monopolies. Cournot-Nash equilibrium is used for decision making on maintenance problem in Oligopolistic electricity market. The Cournot-Nash problem is modeled as a mixed integer nonlinear programming optimization problem. The analytic framework presented in this paper enables joint assessment of maintenance and generation strategies. © 2011 Praise Worthy Prize S.r.l. -All rights reserved

Multi-Objective Optimal Placement of Recloser and Sectionalizer in Electricity Distribution Feeders

© 2019 IEEE. Electricity distribution feeders, due to their geographical dispersion, are subjected to faults caused by adverse weather, vegetation growth, etc., resulting in long outages for customers. Overhead switching devices (i.e. reclosers, sectionalizers, disconnectors and etc.) are known as the most practical solutions to limit the outage area, and consequently increase the distribution system reliability. This paper presents a Multi-Objective Particle Swarm Optimization (MOPSO) algorithm for Optimal Placement of Recloser and Sectionalizer to minimize customers' outage cost and increase system reliability with an optimal investment. The algorithm determines the number and optimal locations of reclosers and sectionalizers to fulfill the objectives. The obtained results on the standard 85-node distribution feeder validate the effectiveness of the proposed method

Time-of-Use Tariff with Local Wind Generation

Renewable energy, such as wind power, is known to significantly reduce system costs and carbon emissions. However, traditional Time of Use (ToU) tariffs fail to account for local energy generation. To overcome this limitation, we propose a mechanism for calculating new ToU tariffs that incorporates Agile ToU and local energy resources, such as a wind farm. By partially supplying local consumption, wind energy can reduce electricity costs for consumers and encourage load shifting towards peak renewable energy production periods. We demonstrate the effectiveness of the proposed mechanism by testing it on a case study of a residential area in Wales, UK, where electricity would be partially supplied by a nearby wind farm with 5 turbines through a Power Purchase Agreement (PPA). The results show that the new tariff significantly reduces electricity bills

Energy Management Strategy of Microgrids Based on Benders Decomposition Method

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. This paper discusses an optimal energy management system for microgrids, taking into account distribution power flow and dynamic loads, in presence of storage units and all associated constraints, aiming to reduce microgrid costs under two grid-connected and islanded modes. Getting the unit commitment, the microgrid energy management problem is introduced as a mixed integer nonlinear problem (MINLP). Since solving MINLP problems is complex and time consuming, a linearization technique is applied for simplification of the problem as a mixed integer linear programming (MILP) problem. Then, the Benders decomposition method is used to reach an efficient and accurate answer. The model proposed is implemented on a 14-bus microgrid including conventional and renewable distributed resources, storage units, and dynamic loads. The results indicated fair and fast performance of the proposed model