Write up on PSS tuning methods Literature survey has been done on the topic to find out the various methods of tuning the power system stabilizer of generators connected to the grid. A few of the methods have been briefly discussed in this write up. In a multi-machine power system various electromechanical oscillation modes are encountered and there are chances that these oscillations will increase when the structure of the system (weak connections between coherent groups of generators), or various disturbances (loss of lines etc) further reduce the inherently small damping of one or more critical modes. When undamped electromechanical oscillations emerge in such cases their amplitude can increase over several minutes and they are accompanied by frequency and voltage fluctuations. Loss of synchronism may then lead to partial or complete collapse of the power system. Power System Stabilizers (PSSs) [2] are an effective way for damping of intra-area and inter-area oscillations in a power network. PSS provides effective supplementary control by supplying auxiliary control signals to the excitation system of the generators. The proper tuning of PSSs has a significant influence on its effectiveness in providing the required damping under different operating conditions and disturbances. Ferraz et al describe a method in which the problem of coordinated tuning of PSS in multimachine systems is studied. They describe a method for the coordinated gain tuning of PSSs, considering multiple operating points. The partial pole placement through the tuning of stabilizer gains is formulated as a nonlinear least squares problem, whose solution is obtained by the Newton method. The original problem is divided into various subproblems, which are s... ... middle of paper ... ...tem to instability if one of these eigenvalues is located close to the imaginary axis which is generally the case for most of the electromechanical oscillation modes. Population based methods [4] are very popular as global optimization techniques and PSO, GA, etc. are used for PSS tuning problems. In a multi-machine environment, the PSS tuning problem has to deal with a large number of unknown variables which leads to a very common experience combinations of those parameters give rise to very close or almost equal fitness values, indicating that there are several closely placed local minima. Due to this characteristic of the problem, the conventional algorithms like PSO and GA are trapped to the local minima in most cases. Mitra et al [4] provide a comparative study of the performances of four advanced population based techniques in tuning the parameters of PSS
Abstract — Partially Observable Markov Decision Processes (POMDP) has been widely applied in fields including robot navigation, machine maintenance, marketing, Medical Diagnosis, and so on [1]. But its exact solution is inefficient in both space and time. This paper investigates Smooth Partially Observable Value Approximation (SPOVA) [2], which approximates belief values by a differentiable function and then use gradient descent to update belief values. This POMDP approximation algorithm is applied on pole-balancing problem with regulation. Simulation results turn out this regulated approach is capable of estimating state transition probabilities and improving its policy simultaneously.
Today, engineers rely on damping systems to counteract nature's forces. There are many types of damping systems that engineers can now use for structures, automobiles, and even tennis rackets! This site focuses on damping systems in structures, mainly architectural variations of the tuned mass damper.
Sligte, D. J., de Dreu, C. W., & Nijstad, B. A. (2011). Power, stability of power, and
My knowledge of engineering is reasonable and includes transformer substations, power plants, power distribution and transmission systems, industrial motor control and PLC programming, protective relay coordination, FACTS devices, grounding systems, Matlab programming and project management. In addition, I possess practical experience performing power flow, short-circuit and relay coordination analyses while using a power system modelling software such as ETAP, EDSA, DigSilent and CYME. Consequently, the aforementioned experience and solid engineering education along with your training will allow me to provide support to operating and new
On August 14th, 2003, a major blackout swept across portions of the northeastern United States and Canada. It was reported that a series of equipment outages in the Midwest led to uncontrolled cascading outages of power transmission lines and generators serving parts of the Northeast, Midwest and Canada. Automatic protective systems operated to open circuits and shut down power plants to prevent further spread of the outages. This is very similar to what happened in The Great Northeast Blackout of 1965. In both situations, the “grid system” shut down one generator in line at a time to protect a surge from the station before it.
times, when there's peak demand of electricity that interacted nature of the grid makes the
...ional standards. Our Security index remained steady as our control measures met the goal of being proactive enough to prevent, sustain, and repudiate a good amount of cyberattacks. The downtime, unfortunately, was more than we planned. But unlike other sectors, the electrical grid is a more complex system when one area is affected. It often requires isolation of systems to get the components back on line and at full operations range before restoration commences. Isolation can also translate to the significant amount of time to properly re-cycle the systems before it is ready to be integrated into the grid. Lastly, the profit margin is hit when the downtime increases. The profits evaporate in fines paid to the state, and federal entities regulating the energy sector. Also, profits are not being generated when power producing systems are isolated from the grid.
The emergence of the Microgrids came after realizing that the architecture of the electricity grid existing nowadays (Figure 1) is getting obsolete, since it is based on the idea of a top-down system, which is predicated on unidirectional energy flows. [ASMUS09]
The PSS is an additional control system, which is often applied as a part of an excitation control system. The basic function of the PSS is to apply a signal to the excitation system, producing electrical torques to the rotor in phase with speed differences that damp out power oscillations. They perform within the generator’s excitation system to create a part of electrical torque, called damping torque, proportional to speed change. A CPSS can be modeled by a two stage (identical), lead-lag network which is represented by a gain K and two time constants T1 and T2. This network is connected with a washout circuit of a time constant Tw. The signal washout block acts as a high-pass filter with the time constant Tw that allows the signal associated with the oscillations in rotor speed to pass unchanged. Furthermore, it does not allow the steady state changes to modify the terminal voltages. The phase compensation blocks with time constants T1i – T4i supply the suitable phase-lead characteristics to compensate the phase lag between the input and the output signals. The commonly used structure of the PSS is shown in Fig
Genetic Algorithms provide a holistic search process based on principles of natural genetics and survivals of the fittest……
For the prevantion of the electricity blackout we need to build smart power grid. A modernized electrical grid that uses analog or digital information and communications technology to gather and act on information, such as information about the behaviours of suppliers and consumers is known as a smart grid. This is used to improve the efficiency, reliability, economics, and sustainability of the production and distribution of electricity in an automated fashion[12]. The important aspects of smart grid is to electronic power conditioning and control of the production and distribution of
...imal solution. Then, a simulation method is developed to compare the centralized and decentralized SCs. In addition, to reach the near optimal solution in the centralized model, evolution strategy (ES) algorithm and imperialist competitive algorithm (ICA) as meta-heuristic approaches are applied.
Background: The increasing require of electricity, fast exhaustion of fossil fuels, diminution of CO2 emissions, in conjunction with the incapability and ineffectiveness of present electricity grid are motivating chief changes in electricity production, circulation and consumption guides around the globe. In recent times, smart electricity grid configurations comprised with interlinked small or medium dimension generators, energy storage elements as well as power electronic technologies have been germinated to find the key limitations of the conventional grid structure. Microgrids are major ingredients of these promising grid configurations. Even though microgrids are received as feasible solutions to power stability and quality topics in ac power systems, the ambiguity in the capacity of microgrids are to deal with serious changeable load and fault situation is the most important pertain in the function of these novel grid configurations.
Even in places where generators are used to provide backup power, the UPS ensures that the loads are maintained during the short interval between the power failure and the time the generator comes up to power the load; - usually from several seconds to a few minutes.
Decentralization of energy system is process of dispersing energy or redistributing energy from central location. [1] Currently, in the world large centralized facilities provide final form of energy from primary energy sources, such as oil refineries and power plants. These plants distribute energy over long distances which effect the overall efficiency. Depending upon different factors like health, environmental and economic etc. energy production systems are built away from the cities or near to the cities. Decentralized energy system not only fulfill rural needs but also able to provide centralized energy production in urban areas. [2]