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A new adaptive load shedding method based on the artificial neural network (ANN) and power flow tracing is proposed in this paper. The ANN is used to estimate the total active power imbalance according to the time interval of frequency drop of the equivalent inertial center from the rated value to the threshold. Load frequency regulation factor and the load priority are incorporated into the power...
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...
Uncertainties in frequency regulations (FR) of generators and loads, and their effects on probabilistic power flow (PPF) analysis are addressed in this paper. The conventional PPF analysis is based on power flow model, without considering the frequency regulation. However, according to frequency regulation characteristics, generation outputs and load demand will respond to frequency deviation. Furthermore,...
The focus of this paper is to examine a controller for a battery energy storage system (BESS), which would reduce the number of deep discharge cycles, with a minimal effect on the regulation services provided by the BESS. Reducing the number of cycles will extend the life expectancy of the BESS, making it a more viable option for the integration of renewable energy onto the power system. To achieve...
This paper proposes a cascading outages model which captures power system operations, protections, automatic regulations, and remedial action schemes. It is based on linear implicit AC PF, which provides a tradeoff between computationally expensive AC PF and approximate DC PF. Combinations of several types of failures and interactions in blackouts are represented, i.e., cascading line overloads, large...
In this paper, the traditional automatic generation and control (AGC) two-area system under deregulated environment with distributed renewable (Solar) energy system has been developed. The concept of DISCO participation matrix is used to simulate the poolco based and bilateral contract with contract violation. Also due to intermittent nature of renewable energy sources increases the frequency deviation...
The significance of interconnected power system is growing day-by-day as many a times the availability resources for electric power generation depends on geographical locations and is distributed in nature. At the same time the strengths of demands are not uniform in a country like India. Hence to mitigate the gap between power generation and demand, especially in a country like India, interconnected...
In an interconnected multi-area power system, as a power load demand varies randomly, in the case of any small sudden load change in any of the areas, both area frequency and tie-line power flow interchange also vary. The main goals of Load Frequency Control (LFC) are, to hold the frequency and the desired power output in the interconnected power system at the scheduled values and to control the change...
In Japan, the deviation in frequency caused by the increase in the amount of renewable energy introduced in power systems soon will become a major problem. Researchers use storage batteries for power systems to balance supply and demand. However, storage batteries are still inferior to pumped-storage plants in terms of cost and durability. In this paper, we propose a novel LFC method using a disturbance...
The unstable output of renewable energy sources, such as wind turbines or photovoltaics, causes various issues in power system operation. With a large number of renewable energy sources, it is well known that the supply and demand balance control becomes a difficult issue. In addition, together with the progress of the electric power deregulation, the power flow problem will be more complex and important...
This paper describes an algorithm for the identification of rare events with high severities, potentially leading to blackouts in power systems, and the quantification of the risk a given system state holds. Based on the method of probabilistic load flow, probability density functions of the branch loadings under consideration of the forecast uncertainty are determined. From that branch tripping probabilities...
Congestion management of power flow in transmission lines using hydroelectric power generation is examined in the scenario where new wind power generation is installed in a power grid. A method is proposed for determining the optimal dispatch of generation output that maximizes transmission margin and minimizes transmission loss under the constraint that the frequency variation is kept within a tolerable...
This paper introduces a power flow algorithm with automatic load-frequency control devices, including wind farms, to assess the post-disturbance condition of power systems when facing power disturbances. The mathematical formulation of fixed-speed wind generators is put forward based on the steady-state representation of the induction generator. Additionally, the participation of doubly-fed induction...
The main objective of Load Frequency Control (LFC) is to regulate the power output of the electric generator within an area in response to changes in system frequency and tie-line loading. Thus the LFC helps in maintaining the scheduled system frequency and tie-line power interchange with the other areas within the prescribed limits. Most LFCs are primarily composed of an integral controller. The...
This paper presents a methodology to make EV able to contribute to secondary frequency regulation, by participating in Automatic Generation Control (AGC). The aggregator entity is used in this methodology to act as intermediate between the AGC and the EV controllers. The case-study used is an approximation of the Portuguese transmission/generation network, including existing tie lines with Spain,...
Penetrating large amount of renewable energy sources into power system, battery energy storage performs an important role for smoothing their natural intermittency, ensuring grid-wide frequency stability, and suppressing voltage rise caused by reverse power flow. The ubiquitous power grid is one of the concepts as a smart grid in Japanese context, where the total battery capacity can be optimized...
The generation control is becoming increasingly important in view of increased load demand & reducing generating resources. The increasing load demands are posing serious threats to reliable operation of power systems. This is because the increasing load demand leads to lowering of turbine speed (Ns) & therefore reduction of frequency (f) of out put voltage of the generator. The healthy operation...
Wide-area monitoring and control system complements the classical protection systems and overcomes their drawbacks. In such systems a dynamic view of power system, using synchronized measurements in short time intervals, smaller than 20 ms, is available. This new kind of system's information provides a novel preventive control action to prevent system's large disturbances. This paper proposes a new...
This paper presents an overview of the key issues in the use of frequency rate change (df/dt) in power system emergency control schemes. The role of df/dt in designing effective under frequency load shedding (UFLS) plan is discussed. The impact of new variable renewable sources (such as wind and solar units) on system frequency gradient is analyzed, and the need for the revising of frequency performance...
Electricity demand has been rapidly increasing globally. More power plants and transmission lines are built to satisfy the customer demand. However, as distributed generation (DG) costs are less than the combined cost of power plant and expansion of the distribution and transmission systems. DG technologies are becoming potential contributors of electricity supplied by electric utilities. To meet...
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