An active power management strategy in a microgrid having static and rotating generators considering generation limits using water pumping loads
01 Jul 2017-pp 484-488
TL;DR: Simulation in MATLAB/SIMULINK environment is performed and it is concluded that proposed microgrid with water pumping system as dump load ensures economical operation of microgrid.
Abstract: In this paper, control and operation of a microgrid having inverter based solar photovoltaic (PV) and diesel engine is presented. The microgrid is designed to meet rural applications. In the proposed microgrid, a water pumping system is considered as a dump load for ensuring economic operation of microgrid. Three scenarios i.e fully loaded, partially loaded and lightly loaded are considered to evaluate the performance of proposed microgrid. In fully loaded condition, PV operates at MPPT for extraction of maximum power and the diesel generator is operating at rated power. In second scenario, when the power demand is less, PV operates in de-rating mode to avoid operation of diesel generator below minimum operating limits; and thus ensures economical operation of the microgrid. However in lightly loaded condition or in case of low solar irradiation when PV power is already close to zero; a dump load is turned ON to ensure the operation of diesel generator in proper technical range. The paper shows the control of water pump as per the available demand and generation. To verify the performance of the proposed system, simulation in MATLAB/SIMULINK environment is performed and it is concluded that proposed microgrid with water pumping system as dump load ensures economical operation of microgrid.
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TL;DR: In this article , a mixed-integer distributed ant colony optimization is introduced as a novel application in droop controlled islanded MGs to minimize voltage and frequency deviations and system losses, and the optimization problem was formulated as a single and multi-objective problem to allocate a dump load and the optimal droop settings for DG in islanded microgrid (MG) during off-peak hours.
Abstract: In highly penetrated microgrids (MGs), the problem of voltage and frequency deviations exceeding their permissible limits, becomes significant with higher share of renewable based distributed generation (DG). The existing real-time control systems of highly penetrated MGs cannot cope on its own with such deviations, owing to the large generation and demand mismatch mainly during off-peak hours. A dump load (DL) can help with voltage and frequency regulation by consuming excess generation. However, further investigation is required to highlight the importance of optimal DL allocation on the operation of MGs. The mixed-integer distributed ant colony optimization is introduced as a novel application in droop controlled islanded MGs to minimize voltage and frequency deviations and system losses. The optimization problem was formulated as a single- and multiobjective problem to allocate a DL and the optimal droop settings for DG in islanded microgrid (MG) during off-peak hours. The proposed optimization method was teamed up with a special backward/forward sweep load flow method to account for DG droop characteristics and enhance the solution convergence. The method was applied to the IEEE 69- and 118-test systems and validated against competitive swarm and evolutionary metaheuristics. Results have shown that an optimally sized and allocated DL with optimized droop setting could minimize voltage and frequency deviations to an acceptable level, while reducing power losses incurred by the installation of such load into the MG.
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TL;DR: The many different techniques for maximum power point tracking of photovoltaic (PV) arrays are discussed in this paper, and at least 19 distinct methods have been introduced in the literature, with many variations on implementation.
Abstract: The many different techniques for maximum power point tracking of photovoltaic (PV) arrays are discussed. The techniques are taken from the literature dating back to the earliest methods. It is shown that at least 19 distinct methods have been introduced in the literature, with many variations on implementation. This paper should serve as a convenient reference for future work in PV power generation.
5,022 citations
TL;DR: In this article, an autonomous active power control strategy is proposed for ac-islanded microgrids in order to achieve power management in a decentralized manner, which is based on frequency bus-signaling of ESS and uses only local measurements for power distribution among microgrid elements.
Abstract: In an islanded ac microgrid with distributed energy storage system (ESS), photovoltaic (PV) generation, and loads, a coordinated active power regulation is required to ensure efficient utilization of renewable energy, while keeping the ESS from overcharge and overdischarge conditions. In this study, an autonomous active power control strategy is proposed for ac-islanded microgrids in order to achieve power management in a decentralized manner. The proposed control algorithm is based on frequency bus-signaling of ESS and uses only local measurements for power distribution among microgrid elements. Moreover, this study also presents a hierarchical control structure for ac microgrids that is able to integrate the ESS, PV systems, and loads. Hereby, basic power management function is realized locally in primary level, while strict frequency regulation can be achieved by using additional secondary controller. Finally, real-time simulation results under various state of charge (SoC) and irradiance conditions are presented in order to prove the validity of the proposed approach.
225 citations
"An active power management strategy..." refers background in this paper
...In [7] emphasis is given on the limitations of the battery application like cost of SOC maintenance, SOC measurement etc....
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01 Jan 2015
TL;DR: The many different techniques for maximum power point tracking of photovoltaic (PV) arrays are discussed in this paper, where the techniques are taken from the literature dating back to the earliest methods.
Abstract: The many different techniques for maximum power point tracking of photovoltaic (PV) arrays are discussed. The techniques are taken from the literature dating back to the earliest methods. It is shown that at least 19 distinct methods(Algo.) have been introduced in the literature, with many variations on implementation. One of the major concerns in the power sector is the day- to-day increasing power demand but the unavailability of enough resources to meet the power demand using the conventional energy sources. Demand has increased for renewable sources of energy to be utilized along with conventional systems to meet the energy demand. Renewable sources like wind energy and solar energy are the prime energy sources which are being utilized in this regard. The continuous use of fossil fuels has caused the fossil fuel deposit to be reduced and has drastically affected the environment depleting the biosphere and cumulatively adding to global warming. Solar energy is abundantly available that has made it possible to harvest it and utilize it properly. Solar energy can be a standalone generating unit or can be a grid connected generating unit depending on the availability of a grid nearby. Thus it can be used to power rural areas where the availability of grids is very low. Another advantage of using solar energy is the portable operation whenever wherever necessary. In order to tackle the present energy crisis one has to develop an efficient manner in which power has to be extracted from the incoming solar radiation. The power conversion mechanisms have been greatly reduced in size in the past few years. The development in power electronics and material science has helped engineers to come up very small but powerful systems to withstand the high power demand. But the disadvantage of these systems is the increased power density. Trend has set in for the use of multi-input converter units that can effectively handle the voltage fluctuations. But due to high production cost and the low efficiency of these systems they can hardly compete in the competitive markets as a prime power generation source. The constant increase in the development of the solar cells manufacturing technology would definitely make the use of these technologies possible on a wider basis than what the scenario is presently. The use of the newest power control mechanisms called the Maximum Power Point Tracking (MPPT) algorithms has led to the increase in the efficiency of operation of the solar modules and thus is effective in the field of utilization of renewable sources of energy. Solar cell operates at very low efficiency and thus a better control mechanism is required to increase the efficiency of the solar cell. In this field researchers have developed what are now called the Maximum Power Point Tracking (MPPT) algorithms.
146 citations
"An active power management strategy..." refers background or methods in this paper
...Vmppt is the MPP reference voltage and is obtained by implementing Perturb and Observe (P&O) algorithm as described in [10]....
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...Description of DC-AC converter for BLDC motor-pump is beyond the scope of this paper and more details on the same can be found in [10]....
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...al [10], presented the control philosophy and operation of DC-AC converter for BLDC motor based water pumping system....
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TL;DR: In this article, a seamless control methodology has been proposed for a photo voltaic (PV)-diesel generator (DG) microgrid to operate both in the grid connected and islanded mode.
Abstract: In this paper, a seamless control methodology has been proposed for a photo voltaic (PV)-diesel generator (DG) microgrid to operate both in the grid connected and islanded mode It does not require any islanding detection mechanism, to change the control philosophy from the grid connected mode to the islanded mode A second order sliding mode control has been used to control the voltage source converter of the PV source whose set points have been generated by PI controllers The maximum power point tracking algorithm for the PV system has been augmented with an auxiliary signal obtained using the electrical power output of the DG to reduce the output power of the PV system for economical operation of the DG unit The DG unit is regulated with the frequency of the microgrid while the inverter used in the PV system regulates the voltage at the point of common coupling Similarly, if the DG is uncontrollable due to any reason, the PV system is further added with an auxiliary signal based on the frequency deviation to maintain frequency stability Simulation of the system has been carried out in MATLAB/SIMULINK with different levels of insolation and load to verify the proposed control scheme
86 citations
TL;DR: In this paper, a solar photovoltaic array fed water pumping system employing a switched reluctance motor (SRM) drive is presented, where the speed of SRM is controlled by varying the dc-bus voltage of the mid-point converter.
Abstract: This paper presents a solar photovoltaic array fed water pumping system employing a switched reluctance motor (SRM) drive. The electronic commutation of the SRM drive at fundamental frequency offers reduced switching losses in a mid-point converter and considerably increases the efficiency of proposed system. The speed of SRM is controlled by varying the dc-bus voltage of the mid-point converter. A dc–dc Cuk converter operating in continuous conduction mode (CCM) is used for dc-bus voltage control. The CCM operation of inductors helps to reduce the ringing effect and decreases the losses of dc–dc converter. Current and voltage stresses on devices including switching stress of Cuk converter are also reduced in CCM. The Cuk converter facilitates the continuous and smooth input/output currents to SRM drive with boundless region for maximum power point tracking (MPPT) operation. The adjustment in step size of an incremental conductance MPPT algorithm facilitates the soft starting of SRM drive. The proposed system, subjected to dynamically atmospheric conditions is designed, modeled, and simulated using MATLAB/Simulink environment. A prototype of proposed configuration is also developed and its performance is validated with test results for the control of speed over varying insolation levels.
67 citations