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The rapidly rising penetration level of distributed generators (DGs) increases the risk of unacceptable voltages in distribution systems. The conventional voltage regulation devices are limited by physical constraints in their ability to perform voltage/var control in response to photovoltaic (PV) output fluctuations. However, the reactive power capability of PV inverters alongside with conventional...
To face the massive integration of Distributed Renewable Energy Sources (DRES), Distribution System Operators (DSO) need to evolve, especially in the operational planning of their networks. In this context, this paper presents a formulation for the Active Distribution Network (ADN) operational planning (OP) problem employing a Second Order Cone (SOC) relaxation of the Optimal Power Flow (OPF). For...
The increasingly introduction of Photovoltaic (PV) systems into residential power system because of customers' desire to reduce electricity supply cost causes detrimental impacts, e.g. voltage operation and voltage unbalance (VU) issues. In order to cope with these problems, the control strategy of PV units where both reactive power control and active power curtailment are allowed has been proposed...
This paper presents a novel concept for combining network and market or system service-orientated functions in grid storage systems. For this, a network service consisting in local phase balancing for power flows or voltages is considered. This service can be combined with further system or market — orientated services. A theoretical formulation of the converter set-points is provided for the use-case...
In this paper, the problem of placement and rated power of capacitor banks in the Distribution Network (DN) is considered. We try to suggest the best places for installing capacitor banks and define their reactive power. The considered formulation requires the optimization of the cost of two different objectives. Therefore the use of properly multiobjective heuristic optimization methods is desirable...
This paper presents a new islanding detection method based on the difference of the power transfer angle between the distributed generation and local load. After islanding, current id and iq will be changed by adding the variation to d_q transformation block of current. This makes voltage and frequency disturbance and therefore islanding is recognized. Active islanding detection method usually has...
Load shedding is the latest and most expensive operation action in order to prevent the loss of voltage and frequency of electricity networks. In this paper LS (load shedding) is occurred by means of four-step frequency relays and five-step frequency and voltage relays which consider the importance of loads and their priority.
We consider the problem of controlling the reactive power injection of microgenerators to regulate the voltage profile in a power distribution network. We consider a large class of purely local controllers including most of the solutions proposed in the literature, and we show that these strategies do not guarantee the desired regulation; namely, that for each of them there are equilibria that are...
A shunt compensator is developed in the paper for power flow balancing in a three-phase distribution-level microgrid with single-phase distributed generation units and loads. The symmetrical components decomposition of the three-phase currents in the microgrid is performed to derive a compensation scheme for the compensator. With the on-line compensation of the compensator, the power source offers...
The massively dispersed nature of power distribution networks and their current unobservability will drive distribution utilities to hierarchize the integration of automation in their systems. Given the complete lack of real-time information in Low Voltage (LV) networks, state estimation techniques specifically tailored for these systems will not come for the foreseeable future. Considering delayed...
Conservation voltage reduction (CVR), the theory that reducing distribution feeder voltages will result in a reduction in demand, has recently been reintroduced with the aim of improving overall energy efficiency. Although CVR is a simple and cost-effective scheme, reducing voltages may not always be the most beneficial decision in terms of reducing demand. In fact, for certain types of load, reducing...
The amount of photovoltaic (PV) generation that can be hosted by existing radial distribution feeders is inherently limited by system constraints and operating conditions. This paper discusses an analysis to determine the photovoltaic hosting capacity of an existing radial distribution feeder. This analysis also visualizes the location-dependence of hosting capacity, and tests the effectiveness of...
The introduction of energy storage devices represents an important element for supporting the operation of distribution networks. Considering the presence of renewable energy sources, the use of these devices provides ancillary services and energy balance flexibility to the network. This work presents a mixed integer second order cone programming model for solving the problem of allocating energy...
Time-varying renewable energy generation can result in serious under-/over-voltage conditions in future distribution grids. Augmenting conventional utility-owned voltage regulating equipment with the reactive power capabilities of distributed generation units is a viable solution. Local control options attaining global voltage regulation optimality at fast convergence rates is the goal here. In this...
This paper proposes a control strategy for harmonic power sharing in an islanded microgrid, without affecting the voltage quality at the load bus. The harmonic power distribution in islanded microgrid depends on the line impedance. The proposed control strategy employs negative virtual harmonic impedance to compensate the effect of line impedance on harmonic power delivery. The influence of mismatched...
This paper presents an approach for generating simplified secondary circuit models with limited SCADA and PV micro-inverter measurement data. The proposed method is computationally efficient and can be utilized with typically available measurement data. The method is applied to models of three real U.S. utility feeders with PV micro-inverter measurements. The proposed simplified secondary circuit...
This paper proposes a method for the coordinated control of power factor by means of a multi-agent approach. The proposed multi-agent system consists of two types of agent: feeder agent (F_AG) and bus agent (B_AG). In the proposed system, the F_AG plays as an important role, which decides the power factors of all distributed generators by executing the load flow calculations repeatedly. The voltage...
The recent development of dispersed generation leads to fact that distribution grids have to deal with the bidirectional power flow which may cause voltage rise above permissible level. Currently used voltage regulation scheme cannot completely and successfully cope with this problem. As a result of the further increasing penetration of distributed generation, the new voltage regulation system will...
This paper proposes a method to investigate the potential of Reactive Power Control (RPC) to maximize the utilization of installed PV sources in distribution grids. Different RPC approaches are examined in combination with distributed storage, grid expansions and curtailment. Simulations are carried out on reference distribution grids, representing remote, rural and urban networks. Varying shares...
Environmental concern on fossil fuel power plants has been one of the drivers for the growth of renewable energy (RE) plants, particularly solar PV (SPV). Hence, it is imperative that the SPVs are connected to the power grid at suitable location to reduce technical losses and also provide peak load shaving. This would also require the determination of appropriate sizing and power factor of SPVs to...
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