S. Chowdhury

Planned Scheduling for Economic Power Sharing in a CHP-Based Micro-Grid

At the planning of combined heat and power (CHP)-based micro-grid, its distributed energy resources (DER) capacity is to be selected and deployed in such a way that it becomes economically self-sufficient to cater all the loads of the system without utilitys participation. Economic deployment of DERs is meant to select optimal locations, optimal sizes, and optimal technologies. Optimal locations and sizes, which are independent of CHP-based DERs types, are selected, here, by loss sensitivity index (LSI) and by loss minimization using particle swarm optimization (PSO) method, respectively. In a micro-grid, both fuel costs and NOx emissions are, mainly, dependent on types of DERs used. So the main focus of the present paper is to incorporate originality in ideas to evaluate how different optimal output sets of DER-mix, operating within their respective capacity limits, could share an electrical tracking demand, economically, among micro-turbines and diesel generators of various sizes, satisfying different heat demands, on the basis of multi-objective optimization compromising between fuel cost and emission in a 4-DER 14-bus radial micro-grid. Optimization is done using differential evolution (DE) technique under real power demand equality constraint, heat balance inequality constraint, and DER capacity limits constraint. DE results are compared with PSO.

Impact of Strategic Deployment of CHP-Based DERs on Microgrid Reliability

Optimal deployment, with respect to locations, capacity sizes, and types of distributed energy resources (DERs), which are the main components in a microgrid system, are chosen for study in this paper. For the selection of optimal locations of DERs, the loss sensitivity index of each bus is taken into account. Whereas optimal size and its separation among microturbines, diesel generators and combustion turbines at each bus location are performed on the basis of the maximum benefit-to-cost ratio of the microgrid owner, obtained by using the particle swarm optimization technique and with respect to their reliable catering and quality of power as well as heat (i.e., combined-heat-and-power (CHP) operation) for customers. This paper conducts four separate case studies-two on 6-bus systems (radial and meshed) and resting on 14-bus systems (the IEEE system and radial system)-to show how much these systems are economically feasible for investment planning when cost and CHP benefits of various types of DERs are taken into account. Load profiles, tariffs, as well as the constructional cost of the microgrid itself are addressed in the six-bus meshed network and its central DER location in a district-heating paradigm is also done separately.

Smart grid initiative for power distribution utility in India

After enactment of Electricity Act 2003 in India, a comprehensive change is happening in Indian power sector, and power distribution utilities are going through a reformation process to cope up with the regulatory change for reduction in Aggregated Technical and Commercial Loss, improvement in Power Quality, Reliability of Power Supply, Improvement in Customer Satisfaction and rationalization of electricity tariff. Apart from restructuring and unbundling of the power sector there is a need for introduction of ‘smart grid’ technology to increase the operational as well technological efficiency of the power distribution network to meet the growing energy demand of India in line with the GDP growth of the country. Smart Grid is sophisticated, digitally enhanced power systems where the use of modern communications and control technologies allows much greater robustness, efficiency and flexibility than todays power systems. A smart grid impacts all the components of a power system especially the distribution level. One subset of smart grids is smart metering / advanced metering infrastructure (AMI) etc. In a smart grid, all the various nodes need to interconnect to share data as and where needed. Smart Grid envisages providing choices to each and every customer for deciding the timing and amount of power consumption based upon the price of the power at a particular moment of time, apart from providing choices to the consumer and motivating them to participate in the operations of the grid, causing energy efficiency and accommodating all generation and storage options, Smart Grid also envisages various properties for the Grid like self-healing and adaptive The suite of Smart Grid products and technologies help maximizing system uptime, while also helping the utility more quickly to restore power to homes and businesses in the event of an outage. Government of India has recently formed “Smart Grid Forum” and “Smart Grid Task Force” for enablement of smart grid technology into Indian Power Distribution Utilities as a part of their Smart Grid initiative to meet their growing energy demand in similar with the developed country like USA, Europe etc.

Modeling and Performance Analysis of a Microturbine as a Distributed Energy Resource

This paper presents modeling, simulation, and analysis of load following behavior of a microturbine (MT) as a distributed energy resource (DER). The MT-generator (MTG) system consists of the MT coupled to a synchronous generator. Simulation is done in MATLAB for different loading conditions under islanded and grid-connected modes. The MTG model also incorporates a speed controller for maintaining constant speed at variable loads. Performance is studied both with and without the speed controller. The paper also compares the simulation results with already reported results and with real life load following data for a typical islanded MT of similar rating.

Optimal PMU placement: A comprehensive literature review

This review outlines the benefits that Phasor Measurement Unit (PMU) integration has on the power network. It reviews past optimal placement techniques covering meta-heuristic and deterministic algorithms. Three best performing algorithms are chosen in terms of minimum required number of PMUs for full system observability. It concludes that Integer Linear Programming (ILP) is the most adaptable mathematical form to model a network. ILP shows the most adaptability in terms of modeling network contingencies and phased installation of PMUs. Further work will focus on developing a hybrid state estimation algorithm for improving state estimation on a medium term basis of 3–5 years.

Islanding protection of distribution systems with distributed generators — A comprehensive survey report

Anti-islanding protection schemes currently enforce the DGs to disconnect immediately for grid faults through loss of grid (LOG) protection system. This greatly reduces the benefits of DG deployment. For preventing disconnection of DGs during LOG, several islanding protection schemes are being developed. Their main objectives are to detect LOG and disconnect the DGs from the utility. This allows the DGs to operate as power islands suitable for maintaining uninterruptible power supply to critical loads. A major challenge for the islanding protection schemes is the protection co-ordination of distribution systems with bi-directional fault current flows. This is unlike the conventional overcurrent protection for radial systems with unidirectional fault current flow. This paper presents a comprehensive survey of various islanding protection schemes that are being developed, tested and validated through extensive research activities across the globe.

Setting of market clearing price (MCP) in microgrid power scenario

Microgrid comprises an interconnection of various low voltage, small-scale distributed generators (DGs), energy storage devices and controllable loads interfaced through fast acting power electronic devices in an isolated remote area as islanding operation where conventional grid is not available. Combined heat and power (CHP) produced by DGs may be utilized in the local market making the microgrid most efficient and economic. Like deregulation regime in conventional power market, multi agent generator providers also may be considered to make the microgrid market equal competitive. The basic objective of a competitive electricity market is to serve the consumers at a reduced price. The objective of this paper is to analyze and propose the pricing mechanism for microgrid energy in the competitive electricity market where the microgrid central controller (mucc) is made to participate in the bidding process to settle market-clearing price (MCP). Two important market settlement techniques, day-ahead and real-time, have been considered with the marketing strategies of renewable DGs like photovoltaic (PV) and wind generation.

Strategic deployment of CHP-based distributed energy resources in microgrids

Distributed Energy Resource (DER) technology (e.g. microturbine, fuel cell) has greatly been advanced in recent years. These DERs are often used as the main components of a CHP-microgrid system and may be called as CHP-based DER. CHP-based DERs can provide power and heat with reliability and quality tailored to the requirements of end-users. As deregulation regime is penetrating more and more into the electricity market, competition among the IPPs is becoming acute. To sustain in this market, cost of electricity generation is to be reduced, not only using modern CHP-based DER technology but also, at the same time, deploying them in the microgrid system as per their type, capacity-size and bus-location. A cost-benefit analysis based method is proposed, in this paper, to enhance the reliability of both 6- and 14-bus meshed as well as radial microgrid networks. In this regard, various costs and benefits relating to CHP-based DER deployment have been taken into account for economic feasibility study. Higher the value of benefit to cost ratio (BCR), than one, better will be the selection of type, capacity-size, and bus-location of CHP-based DERs in respect of utilitys benefit. More the Utilitys benefit, lesser will be the price of electricity and ultimately, gainer will be the consumers. In this paper, bus-locations have been selected by loss sensitivity analysis and Particle swarm optimization (PSO) technique has been used to maximize BCR.

ANFIS based automatic voltage regulator with hybrid learning algorithm

In this paper, the authors propose a design methodology of adaptive neuro-fuzzy inference system (ANFIS) based automatic voltage regulator (AVR) using hybrid learning algorithm to improve the small-signal performance of power system. Here, a zero order Sugeno fuzzy model is considered, whose parameters are tuned off-line through hybrid learning algorithm. This algorithm is a combination of least square estimation and error backpropagation method, where the least square method is applied for the tuning of linear output membership function parameters and the backpropagation method is used to tune the nonlinear input membership function parameters. The proposed method is verified through digital simulation with a single machine infinite bus system. It is found that the AVR is performing well in restoring the terminal voltage instantaneously and the damping characteristics of the rotor angle are also improved. The simulation results establish that the design of ANFIS based AVR employing hybrid learning algorithm can be very useful in small signal stability of power system.

Modelling and simulation of microturbine in islanded and grid-connected mode as distributed energy resource

This paper presents modeling and simulation of microturbine (MT) to analyze its load following performance as distributed energy resource (DER) with general as well as critical priority loads. The system comprises of a synchronous generator and a MT coupled to it. Simulations are carried out in islanded and grid-connected mode of the system to observe its behavior when supplying customerpsilas variable loads. It also incorporates modeling and simulation of microturbine with a speed control system of the MT-synchronous generator to keep the speed constant with load variation. The load following characteristics is observed and validated for this MT-synchronous generator model in Matlab-Simulink environment with power system block sets. This is applicable with combined heat power (CHP) generators both with general fuel as well as bio-fuels. The use of bio-fuels is very much promising for generating green power preventing green house gas emissions for fighting against global warming. But it may take some time to be in the market place for its commercial use.