International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 04 | Apr -2017
p-ISSN: 2395-0072
www.irjet.net
ENHANCEMENT OF TRANSIENT STABILITY OF SMART GRID ROHIT GAJBHIYE1, PRALAY URKUDE2, SUSHIL GAURKHEDE3, ATUL KHOPE4 1Student
of Graduation, Dept. of Electrical Engineering, ITM College of engineering, Maharashtra, India of Graduation, Dept. of Electrical Engineering, ITM College of engineering, Maharashtra, India 3 Assistant professor, Dept. of Electrical Engineering, ITM College of engineering, Maharashtra, India 4 Assistant professor, Dept. of Electrical Engineering, ITM College of engineering, Maharashtra, India
2Student
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Abstract - This paper gives the solution for enhancement of
transient stability of smart grid connected squirrel cage induction generators. In most of the wind power plant induction generator is popular because it has low cost and low maintenance. Fault occurs in power system leads to over speed of rotor, consequently the over speed of rotor introduced transients in power system after clearing fault. If the transients are withstanding for more time in the system, the system will have difficult to stable the transients. So, for this paper deals with the transients stability enhancement of smart grid connected squirrel cage induction generator by using plugging mode operation and stable the transients after clearing the fault. Simulation results show that the proposed method can be effective in enhancing the transient stability. Since in this method, there is no need for accessory equipment, the proposed method is more attractive from the economic point of view.
Key Words– induction generators (IGs), Plugging mode, squirrel-cage, transient stability, wind turbine. 1.
INTRODUCTION Now days Smart Grid gives a reliability which provide continuous power and if fault occur in system which will clear the fault as early as possible and reclose system as normal. The smart grid makes use of technologies such as state estimation, that improve fault detection and allow self-healing of the network without the intervention of technicians [1]. This will ensure more reliable supply of electricity, and reduced vulnerability to natural disasters or attack. In smart grid harmonics are present that disturbs the system frequency that develops transients in smart grid. In recent years, wind energy has become one of the most economical renewable energy technologies. Today, electricity generating wind turbine proved and tested technology, and provide a secure and sustainable energy supply. At good windy sites wind energy can already successfully compete with conventional energy production. Many wind power generator are induction machines, either squirrel cage or wound rotor if under
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the condition of high power induction generator connected to weak networks, there is possibility of transient instability of smart grid connected induction generator.
At staring induction machine operates as motor till the rotor speed is greater than synchronous speed therefore the slip of induction motor is negative and induction machine acts as generator and delivers a power supply to smart grid. When faults occur on system it leads to rotor instability as well as voltage instability. But when fault is cleared rotor speed is too high that takes more time to become steady state Previous researches have revealed that flexible ac transmission system (FACTS) devices, rotor circuit control and braking resistors are there methods that can improve the IGs stability. In [2] FACTS devices provide and absorb the reactive power in regulating manner of transmission line hence stability has maintained. In [3] and [4] SVC and STATCOM are the facts devices which considerably improves system stability during and after disturbances. Also in [5] , the effect of unified power flow controller (UPFC) on improving the rotor speed stability and voltage is stable solution based on FACTS devices have been a recognized as expensive method. In [6] and [7] rotor circuit have been investigate one possibility is to employ and a electronically controlled external resistance connected with rotor winding and another one is to control the voltage applied to rotor through converter in doubly fed IG, however this method is only applicable to the slip ring rotor or wound rotor type IG and cannot be applied to squirrel cage type IG. In [8] and [9], using braking resistor technique is introduced as a solution for improving transient stability enhancement of IG. Application of this method for transient stability enhancement of synchronous generator has been investigated for many years [10]. The braking resistor decreases rotor speed hence improves transient stability by absorbing electrical power during fault however the operation of IG is significantly different form synchronous generator and therefore the braking resistor is less effective ISO 9001:2008 Certified Journal
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