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AUTOMATIC generation control (AGC) has been used for several years to meet the objective of maintaining the system frequency at nominal value and the net tie line power interchange from different areas at their scheduled values. One of the main components of AGC is Load frequency control (LFC), one of the major requirements in providing reliable and quality operation in multi-area power systems. In...
Underlining first the principle of Load Frequency Control (LFC) according to the UCTE regulations this paper also presents simple continuous time models identified for the main hydro and thermal power generation units used by the LFC in Romanian Power System. Different models were proposed in previous articles but they are very complex for LFC studies. An experimental identification procedure based...
This paper uses methods from stochastic analysis and stochastic modeling to determine the impact of a certain trading limit on the transfer between the two areas of a benchmark two-area power system. We also try to state which uncertainties are important to consider when calculating this power transfer.
In electrical power systems must always be a balance between supply and demand. Any imbalance will result in a frequency deviation. To reduce the imbalance to zero, ancillary services for balancing are in use. Ancillary services are characterised by their deployment time and their capacity. By using discrete Fourier transform, the kind of ancillary services as well as the requirements for balance...
In order to take full advantage of interconnected power system, a new distribution mode of AGC adjustment responsibility is proposed to pursue better frequency quality. Under this distribution mode, various areas AGC can adjust the entire electrical network power together according to the proportion to the same direction the load variety, regardless of whether the load change occurs in the home area...
Under-frequency load shedding (UFLS) controls are means that usually are taken when generation deficiency occurs and frequencies of power systems are in extreme danger. A new UFLS scheme is designed to maintain the system frequency within an acceptable range for the possible generation deficiencies. The proposed scheme considers the spinning reserve and load models, estimates imbalance power through...
In this paper a new model is proposed to show the interaction between the LFC and the AVR loops. These coupling effects of the AVR and LFC loops are studied by extending the linearized AGC system to include the excitation system. A complete system model for low-frequency oscillation studies should be composed of mechanical and electrical loops. So one machine - infinite bus model of a power system...
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...
`Plug and play' theory is a hot research point in micro-grid. In this paper, a `plug and play' model was set up based on a kind of control technology mixed with power electronics technology and agent technology. A three tiers multi-agent control system (MAS) was established which contained power grid agent, micro-grid agent and components agent, this MAS was used to control different agents and make...
In this paper we present a distributed supervisory strategy for load/frequency control problems in networked multi-area power systems. Coordination between the control center and the areas is accomplished via data networks subject to communication latency which is modelled by time-varying time-delay. The aim here is at finding strategies able of reconfiguring, whenever necessary in response to unexpected...
A new experiment for undergraduates showing voltage and frequency control of a small alternator for a two bus power system is introduced. Voltage and frequency controllers were designed in Simulink and implemented using dSPACE. A subsystem of the scaled down power system testbed developed at Florida International University was utilized to study the effects of varying load on the generator operating...
With the increase in size and capacity of electric power systems and the growth of widespread interconnections, the problem of power oscillations due to the reduced system damping has become increasingly serious. Since a superconducting magnetic energy storage (SMES) unit with a self-commutated converter is capable of controlling both the active and reactive powers simultaneously and quickly, increasing...
Automatic generation control (AGC) has been one of the important issues in the operation of local area and interconnected power systems. AGC provides power demand signals for AGC power generators to control frequency. In AGC, some variables of power system such as frequency and power generation are measured to calculate the area control error (ACE). The ACE value is an important factor of AGC performance...
This paper proposes a structure of an HILS based development system for MMS. This system is composed of RTDS and its hardware interface devices, MMS, communication emulator modules. The RTDS is operated for real-time simulation for both microgrid and microsource models. By using this HILS system, the secondary regulation action of MMS during an islanded operation is evaluated. The secondary regulation...
This paper presents the usage of sliding mode control algorithm for load-frequency control in power systems. One of main obstacles in the usage of sliding mode based load-frequency control is the difficulty in choosing optimal controller parameters. In this paper, appropriate sliding mode algorithm parameters are obtained using integral performance criterion. Those parameters ensure stability, accuracy...
This paper describes an application of Q-learning method based on-line self-tuning control methodology to solve the automatic generation control (AGC) under NERC's new control performance standards (CPS). The AGC problem is a stochastic multistage decision problem, which can be modeled as a Markov decision process (MDP). This model-free Q-learning algorithm regards the CPS values as the rewards from...
Design of a robust PID controller for load frequency control of non-minimum phase hydro power plants using the quantitative feedback theory (QFT) is addressed in this paper. Motivated by the large uncertainty in dynamic models of power system components this paper proposes a simple and systematic procedure to tune the parameters of the controller. The resulting controller in simulation results is...
A study is described of the load frequency and tie-line power control of a multi-area interconnected power system, using self tuning control based on a minimum variance strategy. Each area in the interconnection is represented by a stochastic ARMAX model and area generation control is computed by a self tuning algorithm with an extended recursive least squares technique for parameter estimation. It...
The load-frequency control models of a two-area interconnected power system with stiff and elastic tie-line are investigated with respect to modeling errors. Only multiplicative type modeling errors are considered for robustness analysis. It is shown that the elastic tie-line model presents a higher degree of robustness.
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