a the second symphonious in the field winding to distinguish issues model of decision framework based on ANN considering the is portrayed in . The course of negative-grouping control generator-transformer unit as the ensured object. All the interior stream at the generator terminals was utilized to separate among blame states of transformer and generator have been reenacted to interior and outside flaws. An advanced system that utilizes the produce the required database for the preparation of ANN. positive and negative grouping models of the generator, and Likewise, few instances of deficiencies are created utilizing the voltages and flows estimated at the generator terminals to separate strategy given in . These cases are utilized just amid testing between inward and outside deficiencies is given in . The of the networks. The created ANN has been prepared and tried utilization of multifunctional computerized transfers for generator with RPROP and Genetic Algorithm and the results are analyzed. protection has likewise been examined , . These transfers Amid this procedure, different designs of ANN have been tried utilize advanced blame location calculations include various flag by differing the number of concealed neurons and keeping the pre-preparing prerequisites. quantity of info and yield neurons fixed. Definite depiction about
(3) Even if there are partially huge voids, if their number is small, they are not significantly reflected onto the change of the AC current and dissipation factor, and therefore, the partial discharge test was conducted to analyze the largest discharge magnitude and its pattern. The partial discharge test results showed that maximum size of the void in the target generatorstatorwinding insulations increased compared to the data measured two years before the ground fault, and its pattern was that of the conductor delamination discharge. It is believed that this was because of the delamination between the copper body and insulation as it dramatically expanded by Joule’s heat with the loss of cooling water in the concerned generator.
The V52-890 kW wind turbine is able to operate in fixed power factor mode with a power factor range in the interval from 0.98 capacitive to 0.95 inductive measured on the 690 V generator side and with 100% of rated active power. It is possible to choose other power factor values; however, with reduced active power The V52-890 kW wind turbine is also able to operate in fixed reactive power mode. In the fixed reactive power mode, the wind turbine will generate or absorb reactive power up to 500 kVAr, when the generatorstatorwinding is coupled in delta; however, with decreased reactive power close to the rated power output. The table shows the Electrical data for WTG.
performing inspections within the air gap between generator rotor and stator. While the second part of the paper is used to describe a new robotic system for performing ultrasonic inspections of the generator retaining rings. An overview of the design and construction of each robotic system is provided, along with an explanation of the capability of each system and its associated benefits to the power station owner. The paper also contains several photos to depict the functionality of each technology within a real world context.
In this way a parameter monitoring system for induction motor using Zigbee protocol is realized and tested. It is capable of performing some operations like running the motor through measuring, stopping it, monitoring and controlling all the parameters of the induction motor such as phase voltages, phase currents, winding temperature, speed. All parameter values are transferred to the controlling computer and by using GUI all these parameter values are displayed on the monitor graphically and stored into excel file for a long time monitoring
The relationship between generator speed and wind speed can be hard to discover, which is shown at top plot of Fig. 5. In order to extract the real behaviour of the generator speed against the wind speed, the KSVM is applied as a regression model to find the relationship between generator speed and wind speed. A threshold is also added to help the data selection for this regression model. The bottom plot of Fig. 5 shows the comparison between original generator speed curve and filtered generator speed curve, where the yellow curve indicates the filtered generator speed curve. The relationship between generator speed and wind speed can be revealed clearly now by adapting KSVM regression.
Previous researches have shown that number of high-speed machine applications in direct drives and generator units increases from year to year. This is due to obvious potential benefits of such power installations: reduced dimensions of high-speed electric machine, decreased total weight of installation, increased efficiency of energy conversion. The main purpose of this paper is to select optimal type of electromechanical convertor for such installation. Four types of electrical machines were considered: synchronous machine with permanent magnets, asynchronous machine, inductor machine, switch-reluctance machine. Comparative analysis of designed 4 MW 12,000 RPM generators was conducted for active materials weight and specific power value and conclusions were drawn.
Wind power is one of the renewable energy sources. It has various advantages like, cost competitiveness, environmentally clean and safeness. Large wind farms have stability problems when they are integrated to the power system. A thorough analysis is required to identify the stability problems and to develop measures to improve it. Mostly used wind generator is a fixed speed induction generator, which requires reactive power to maintain air gap flux. Reactive power equipments are used to enable recovery of large wind farms from severe system disturbances. In this paper shunt and series FACTS devices, Static Synchronous Compensator (STATCOM) and Static Synchronous Series Compensator are used for the purpose of stabilizing grid connected wind generator against the grid-side disturbances. The essential feature of the FACTS devices is their ability to absorb or inject the reactive power. Since stability is a non linear process so system performance can be improved by using nonlinear controllers. Neurofuzzy controller (NFC) is a non linear controller. NFC has faster response than conventional PI controllers.
ABSTRACT: As the world is running behind non-renewable sources and we are at the edge of the time to lose all this source. The need for new energy sources had led to a number of alternatives, which have been unaffordable and unavailable due to huge cost and scarcity. In response to this, Dual power induction generator is designed and developed using local materials. The proposal of this, paper is to use fewer amounts of non-renewable sources and to gain full benefit from it the generator comprises an inner stator as first layer and second layer of outer stator in between this two stator assembly magnetic rotor is arranged. In future, it might solve all problems regarding to the power of the world. The driving mechanism of dual power generator is the 0.5hp alternator current motor, powered by a 230-volt power supply, which spines the 600 watts from both terminals of alternator to produce electricity. It is pollution-free and eco- friendly. The test unit was built in March, 2017.
The geometry of the brushes, commutator contacts, and rotor windings are such that when power is applied, the polarities of the energized winding and the stator magnet(s) are misaligned, and the rotor will rotate until it is almost aligned with the stator's field magnets. As the rotor reaches alignment, the brushes move to the next commutator contacts, and energize the next winding. Given our example two-pole motor, the rotation reverses the direction of current through the rotor winding, leading to a "flip" of the rotor's magnetic field, driving it to continue rotating. In real life, though, DC motors will always have more than two poles (three is a very common number). In particular, this avoids "dead spots" in the commutator. You can imagine how with our example two-pole motor, if the rotor is exactly at the middle of its rotation (perfectly aligned with the field magnets), it will get "stuck" there. Meanwhile, with a two-pole motor, there is a moment where the commutator shorts out the power supply. This would be bad for the power supply, waste energy, and damage motor components as well. Yet another disadvantage of such a simple motor is that it would exhibit a high amount of torque "ripple" (the amount of torque it could produce is cyclic with the position of the rotor).
It can be that the steady-state voltage stability limits of induction generator based wind farm with no-load compensation is only 213MW. When more real wind power injects into the POI than 213MW, the voltage will collapse. When the DFIG based wind farm with constant power factor control that control the POI as a PQ bus with Q= 0 MW, the steady-state voltage stability limits are increased largely to 424MW. When 350MW real wind power injects into the grid, the voltage stability margin can be acceptable. It must be noted that induction generator based wind farm with full-load compensation can enhance the voltage stability limit, but not very obviously; the full-load shunt capacitor compensation should not be put into use in low wind power output totally or else that will arise bus voltage higher than acceptable voltage level such as the curve (2). In actual operation of wind farm with full-load compensation, the shunt capacitor should be switched on gradually along with the active power output increasing. Due to the shunt capacitors compensation, the voltage collapse value in case (2) equal to 0.95 pu is higher than that in case (1) or case (3) equal to 0.85 pu. Because the reactive power output of shunt capacitors is proportional to V2 as the grid voltage decreasing, the
This paper puts forward a new magnetic levitation generator, describes its operation mechanism, and derives the formula of levitation forces, then veriﬁes its validity by FEA. Compared with the traditional magnetic levitation generator, the levitation windings are in inner stator, the armature windings are in outer stator, and the distributed hollow rotor is used to separate magnetic coupling between inner and outer windings. This new generator has clear structure and function, which is easy to maintain and control. And the new kind of setting is equivalent to a 2-degree-of-freedom radial magnetic bearing and a common generator. This generator is suitable for the case of short shaft. Meanwhile, this new setting enhances the radial load capacity of the generator, which greatly improves the performance of the levitation. Because there are the least couplings between the armature windings and levitation windings, the complexity of the circuit will be reduced. Generally, the new self-decoupling magnetic levitation generator is a new ideal and new attempt for structural optimization about the wind power generation, which has some certain references for other studies about bearingless motor.
The magnetic border or the yoke of DC motor made up of cast iron or steel and forms an essential part of the stator or the static part of the motor. Its main purpose is to form a protecting covering over the internal sophisticated parts of the motor and supply maintenance to the armature. It also maintenances the field system by covering the magnetic poles and field winding of the dc motor. The yoke portion also keep all the modules inside the motor by dust, gas, moisture etc. Cast iron is toffee, solid and more fusible than steel. It is also nonmalleable, which means that it cannot be strained, hammered or curved into shape. It has a crystal- like construction, and it is weak in stiffness what gives good permeability to material in the motor.
employed in wind turbines. Among induction generators, doubly fed induction generators (DFIG) offer variable speed, while keeping the size of the controllers small so as to reduce the costs. In this thesis, we will compare different DFIG models. When a wound rotor induction machine (WRIM) works as a generator and fed power from both stator and rotor side, it is termed as Doubly Fed Induction Generator (DFIG). DFIG scheme is used as a variable speed fixed frequency topology. In this scheme, stator is directly connected to the grid while the rotor circuit is connected to grid through an AC/DC/AC back to back frequency converter. The rating of this converter is typically 25-30% of the total power rating of the generator. This is the main advantage of DFIG over other variable speed topologies as it provides same features at lesser cost and provides good efficiency. DFIG is basically a wound rotor induction generator which has a stator and rotor circuit. Stator circuit of the DFIG consist of stator frame, laminated stator core having stator slots embedded in it and a balanced 3 phase windings placed 120 degree electrically apart from each other. The winding distributed in nature, are insulated and are housed in the stator slots. Stator windings may be connected in delta or star manner. Rotor circuit consist of rotor, rotor slots and a 3 phase insulated winding. These 3 phase winding is uniformly distributed .These windings are connected to one end to form star connection and on the other side connected to slip rings. The stator circuit is connected directly to grid (or sometimes through a soft stator to minimize the high inrush current). Rotor circuit is connected to grid through a bidirectional AC/DC/AC bidirectional converter.
The biggest challenge of the commercialization of SC generators is the high price of SC wire. For a high temperature superconducting (HTS) generator, the cost of the HTS material could be up to 90% of the total material cost . The iron-cored rotor SC generator topology has gained much attention in recent years, due to better utilization of SC material, although the weight is higher than that of air-cored topologies. The performance has been compared with other topologies in -. Some iron-cored rotor SC generators are designed and the performances are analyzed in -. The influences of design parameters, such as rotor pole width, stator outer diameter, electric loading, operating temperature of the SC wire, etc., on performance are investigated in . DTU investigated the influence of pole number on the weight, SC wire length and active material cost of air-cored rotor SC generator in . Converteam found the optimum pole number to be between 16 and 20  . However, both DTU and Converteam only gave the results without detailing how the results were obtained.
inductance at this rotor position jumps to a higher value and begins increasing as the rotor pole aligns itself with stator pole. Since the phase current is considered to be constant in the simulation therefore, the generated voltage rises as the phase inductance increases. Finally, it reaches its maximum value at half alignment. It is worth mentioning that, at this rotor position, the pole belonging to the next phase state its alignment therefore, some of the magnetic flux is directed to this phase and the magnetic flux density reduces in the first phase. In the third section [50 ◦ , 90 ◦ ], the first rotor pole is in half aligned position and going to full alignment and the second rotor pole moving into half aligned position, therefore the generated voltage drops due to the magnetic flux density reduction in that phase. Finally, in the fourth part [90 ◦ , 145 ◦ ], the rotor pole is going into unaligned position and negative voltage is generated due to the negative slope of the flux linkage curve. The estimated average voltage is about 1 volt for the voltage curve shown in Fig. 12.
This paper presents a small power generation system motivated by a coreless stator AFPM (Axial Flux Permanent Magnet) generator which is driven by the rooftop ventilator. The generator consists of discs for the rotor and the stator geometry. The stator disc is sandwiched between two rotor discs and the magnets in the two opposite rotor discs may be placed N-S arrangements. Since there is no silicon steel inside the coils, we should eliminate the magnetic pulling force between the rotors and the stators. When the ventilator rotates, the flux of the permanent magnet rotors part move across the air gap and induces the emf in the coreless coils. After that, the ac voltage is rectified to dc voltage and finally charged to the 12 V 5 Ahr battery for household appliances. To analyze the magnetic circuit, the finite element analysis was used to simulate the magnetic flux density in the AFPM generator. The test is operated in electrical machines labo- ratory and essentially to determine the characteristics of prototype generator. Based on the experiments, the results of the output voltage can achieve 103 V with no-load, and 20 V on 100 Ω resistive loads at the speed of 200 rpm. For the results after installing the generator on the roof of a building to charge the 12 V battery, the minimum wind speed for enough charging to battery is at 10 rpm. Furthermore, the prototyped of the generator is relatively small and cheap. Af- ter the fabrication and testing of the prototype, this system has been proved feasible for practical application.
In order to deﬁne an adequate dynamic model for the synchronous generator a change of coordinates is neces- sary. The well known reference frame theory provides the basis necessary to obtain a dynamic model that does not include any time-varying coeﬃcient . Since the circuits of the rotor are normally unsymmetrical we will be using the rotor reference frame . Variables associated with the stator of the generator can be transformed from the original coordinates (machine variables) to variables in the rotor arbitrary reference frame, i.e.
This paper studied the direct-drive permanent magnet synchronous machine (permanent magnet synchronous generator, PMSG) Chopper optimal topology and resistance value. Compared the dif- ferent Chopper circuit low voltage ride-through capability in the same grid fault conditions in si- mulation. This paper computes the dump resistance ceiling according to the power electronic de- vices and over-current capability. Obtaining the dump resistance low limit according to the tem- perature resistance allows, and calculating the optimal value by drop voltage in the DC-Bus during the fault. The feasibility of the proposed algorithm is verified by simulation results.
of the voltage transformer connected to generatorwinding terminals . Although the above schemes cannot detect weak faults (such as single turn-turn ones), other methods had been proposed to achieve this goal by considering a model for the statorwinding. P. H Park et al.  proposed the dq0 model in which a sinusoidal distribution is assumed for the machine winding. Using such model, only the fundamental component is recognized and all the higher space harmonics produced by the machine windings are neglected. For example, when a TTF occurs in the machine, the generated flux distribution in the air-gap is no longer sinusoidal and significant space harmonics will be produced in the air-gap magnetic field. Since the dq0 model fails to model internal faults, other models were generally derived in the phase domain [4–9], where the voltage and flux linkage equations are directly developed in the fixed phase reference. These fault models suppose that the ratio between the winding inductances is proportional to the ratio between the effective numbers of winding turns. However, this is acceptable when the windings are concentrated or a pure sinusoidal distribution of magneto- motive force exists in the air gap.