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With the increase of the scale of the power grid and the improvement of the intelligence degree, the rationality and accuracy of the schedule power flow (the schedule) are becoming more and more serious. In this paper, by analyzing the relationship between input and output in the process of power flow calculation, the five main factors influencing the line active power deviation and the main cause...
This paper presents a study about optimization in microgrid with energy storage. The development of technology makes it possible for energy storage utilization as solution for energy management problem due to renewable integration. The ability of energy storage to store and supply power can be used to solve intermittency problem of renewable energy. Furthermore, the possibility of energy storage integration...
Network reduction methods are essential and useful means today for analyzing large, complex power systems with much ease. It is desired that the reduced network represent the original network as closely as possible. Several methods are available in the literature for the reduction purpose. Zhukov’s method of network reduction is well-suited to large system reduction where identity of pertinent...
Load recovery is an important part of network reconfiguration that aims at reconfiguring a stable skeleton network and recovering electrical supply as quickly as possible following a blackout. Considering the load recovery strategy may affect a strategic decision for generator start-up and restoration path selection, it is necessary to comprehensively deal with above three aspects simultaneously,...
One of the biggest threats for the security of power grids are congestion of cross-border lines and congestion in the network itself as result of parallel flows. Nowadays, occurrence of congestion is a result of limited network transfer capacities as a direct consequence of increased power transactions. One of the reasons for cross-border congestions are the unreal cross-border capacities calculations...
The control strategies of micro grid is an important topic for micro grid. With the development of DC micro grid, the control strategies of DC micro grid is drawing more and more attention. Nowadays, the most widely used control strategy of DC micro grid is droop control. All the distributed generators and energy storage systems share loads through different droop coefficients in droop control. This...
DC distribution systems (DCDS) connect local generators and loads directly. By avoiding unnecessary losses in AC-DC conversion, DCDS offers higher energy efficiency. Since different parties in a DCDS may have conflicting goals, matching between power supply and demand should be done with carefully designed allocation rules and monetary transfers, such that no one prefers to act otherwise than the...
The application of semidefinite programming (SDP) to the resolution of the Optimal Power Flow problem (OPF) has recently been the focus of significant research effort. In conjunction with sparsity-exploiting techniques, it can yield globally optimal solutions for well-conditioned large-scale networks. In this paper, we show that these techniques can theoretically be extended to a larger class of problems,...
This paper reviews general problem of generation adequacy indices (GAI) assessment and load shedding management problem in particular. It's shown that mutual power aid strategies and load shedding strategies used in GAI calculations are the main reasons for the difference in results obtained by diverse GAI calculating software packages. The paper presents several load shedding strategies including...
This paper presents a new methodology for allocation of transmission system costs in electricity markets established in one single area or composed by the interconnection of multiple subsystems. Initially, the proposed method allows the decomposition of the total cost of transmission in two installments: the first, referring to the utilized capacity of the network (estimated at a predetermined operating...
This paper aims to propose a secondary control algorithm based on Fuzzy Logic to adjust frequency and voltage in islanded microgrids. It is well-known, that, when a microgrid changes its operation from grid-connected to islanded mode, the time domain variability of the loads will change the frequency and voltage profiles of the system. In this sense, the operation of the system might become unsafe...
Zambia's national power grid is facing a constraint in meeting the present and expected future demand. Solar photovoltaic (PV) power is a promising option for large-scale renewable energy integration in Zambia as there is abundant insolation, averaging 5.5kWh/m2/day. However, large-scale integration of solar will increase the variability and uncertainty in the power supply, which can result in blackouts...
Optimal power flow (OPF) and security-constrained OPF (SCOPF) studies are important tools for both planning and operation of power supply systems. Conventional gradient-based SCOPF methods are commonly used for that purpose, but when analysed system is overstressed with severe multiple contingencies, conventional SCOPF methods may fail to converge. In such cases, meta-heuristic SCOPF methods can be...
Interactions between electricity market models and network models are more and more investigated due to higher international market integration and operation security concerns. In this paper, a procedure for flow-based analysis according to market results is proposed, in order to inspect the effects of new connections under varying operating conditions over a whole year. In particular, aggregated...
The isolated power system of Cyprus is currently in a transition towards an open-access electricity market. One of the challenges that spring from this transition relates to the establishment of a transparent loss allocation method through the use of distribution loss factors (DLFs) that will be applicable in the emerging open-access market environment. To this end, this paper investigates the particulars...
The overwhelming majority of the literature on stochastic planning involves problems that exhibit exogenous uncertainty. In such problems the optimal decisions and the process of uncertainty resolution are independent, with the latter taking place solely with the passage of time. In this paper a novel stochastic planning formulation is proposed that can capture endogenous sources of uncertainty, whose...
Distributed energy resources are shaping the future of power systems. Coordination of these geographically scattered resources motivates the need for adoption of distributed control strategies. This paper presents a fully distributed DC Corrective Security Constrained Optimal Power Flow (CSCOPF) for electricity networks in which the transmission lines are potentially instrumented with Distributed...
Integration of Plug-in Electric Vehicles (PEVs) and renewables poses substantial challenges in electricity distribution networks. This paper investigates the impact of large-scale PEV penetration in distribution networks, when also considering the integration of other renewable energy resources, e.g., wind, hydropower and Photovoltaics (PVs). As such, analysis on an existing low voltage local power...
The installation of distributed generator (DG) is becoming increasingly attractive to utilities and consumers because distributed generation produces energy close to the load, are more efficient with reduced active losses and have less environmental impact. The paper proposed a validated two-step optimization novel technique with full Newton Raphson load flow. In the first step, the optimal size of...
The continued evolution of the grid and renewable systems in today's energy market brings the question of how to best utilize these resources. This question is not limited to the economics or operating constraints of the system. The work presented examines these two aspects of the problem for the battery/storage dispatch. The setup is applied to a 3-bus test system although the work is applicable...
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