An Insightful Steady-State Performance of a Squirrel Cage Induction Generator Enhanced with STATCOM

2014 ◽  
Vol 15 (3) ◽  
pp. 205-215 ◽  
Author(s):  
Olorunfemi Ojo ◽  
Mehdy Khayamy ◽  
Mehari Bule

Abstract This paper presents the regulation of the terminal voltage and reactive power of a grid-connected squirrel cage induction generator. A shunt connected voltage source inverter (VSI) with a capacitor in the DC side operating as a Static Compensator (STATCOM) and a shunt capacitor are used for regulating the generator terminal voltage and limit the reactive power demand from the grid. Simulation results for steady-state operation for a wide variation of speed in the super-synchronous region are presented as well as the dynamic stability of the system. Closed-form steady-state characteristics equations for the system are used to determine key variables and to demonstrate how the operation of the system depends on various parameters. This characteristics curve which contains all of the equations of the system provides the all in one insightful view to the inherent characteristics of the system and the effect of the parameter variation on the terminal voltage plane.

Author(s):  
Pallavi Thakkur ◽  
Smita Shandilya

Self-Excited Induction Generator (SEIG) offers many advantages such as low cost, simplicity, robust construction, self-protection against faults and maintenance free in today's renewable energy industry. However, the SEIG demands an external supply of reactive power to maintain the constant terminal voltage under the varying loading conditions, which limits the application of SEIG as a standalone power generator. The regulation of speed and voltage does not result in a satisfactory improvement although several studies have been emphasized on this topic in the past. To improve the performance of the SEIG system in isolated areas and to regulate the terminal voltage STATic COMpensator (STATCOM) has been modelled and developed in this dissertation. The STATCOM consists of AC inductors, a DC bus capacitor and solid-state self-commutating devices. The ratings of these components are quite important for designing and controlling of STATCOM to maintain the constant terminal voltage. The proposed generating system is modelled and simulated in MATLAB along with Simulink and sim power system block set toolboxes. The simulated results are presented to demonstrate the capability of an isolated power generating system for feeding three-phase resistive loads.


2020 ◽  
Vol 8 (5) ◽  
pp. 4656-4660

The current energy demand scenario leads to tremendous increase in the renewable energy sector, but the integration of these renewable causes various stability issues of the system. Increasing share Wind energy has several shortages due to its energy harnessed from the wind. These shortages can be improved by compensating reactive power into the wind plant. The wind farm consist of fixed speed squirrel cage Induction generator absorbs reactive power from the grid for stable operation and it can be injected using reactive power compensator. In this context, the main aim of the research is to find the minimum reactive power compensation required for stable operation for different rating of Type-1 WTG in grid connected mode. In this paper, a detailed model of constant speed Squirrel Cage Induction Generator is carried out in MATLAB/SIMULINK-2017a to analyze the need of reactive power compensation to maintain voltage and frequency stability of the system during normal condition. The work also focuses on to investigate the impact of induction generator inertia level on compensation level. The modified IEEE 5-bus radial distribution system is used to conduct these investigations and the simulation results clearly show that: (1) The necessity and minimum additional reactive power support to the wind farm to improve and maintain stability of the system; (2) the inertia level of wind farm and reactive power compensator level both are independent each other.


2018 ◽  
Vol 220 ◽  
pp. 05004
Author(s):  
Nguyen Huu Nam ◽  
G.S Mytsyk ◽  
A.V Berilov ◽  
Myo Min Thant

One of the relatively simple (comparatively cheap) and promising solutions of the wind power plant - the wind turbine system (WTS) with variable speed on the shaft of the wind wheel - is to execute it on the basic of an induction machine - IM. Today, the problem of self-excited induction machine is solved in two ways - by using either capacitors, or electronic converters. As a generating system (based on IM), several WTS are often used, working parallel or directly connected to the grid. For induction machine: squirrel-cage induction generator (SCIG) and doubly-fed induction generator (DFIG) are used, several possible types of them are systematized, evaluated and compared on functional features and properties. Based on computer simulations, the ability of DFIG with back to back converters (in the form of two serially connected 2 level voltage source converters - converter-1 and converter-2) is determined in the rotor circuit at a variable speed of the drive shaft (in modes sub-synchronous and hyper-synchronous speeds) give to the grid only active power. For mass-scale and energy indicators, this structure is the optimum for WTS.


Author(s):  
Dominik Andrzej Górski

Purpose The power electronic converter is used for the satisfaction of reactive power demand of induction generator, when grid-tied. This paper aims to present an application of STATCOM to reduce inrush transient caused by the connection of a squirrel-cage induction generator (SCIG) to the grid. Design/methodology/approach The power generation system consists of an uncontrolled prime mover, a SCIG and a power electronic converter connected to the grid. The three-phase Neutral Point Clamped (NPC) converter works as a STATCOM to satisfy a reactive power demand of the generator. A control scheme of STATCOM uses the x-y reference frame rotating synchronously with grid voltage vector and the p-q instantaneous power theory to calculate q component of grid power. Findings It is shown that the parallel converter, which works as a reactive power compensator allows decreasing transients during a grid connection of the induction generator. Research limitations/implications Transients during a grid connection of the induction generator are only partially decreased. Practical implications It is needed to compensate for the reactive power of a SCIG. The NPC converter works as a STATCOM. The converter partially reduces grid transients during generator connection. The laboratory tests are demonstrated by connection 7.5 kW induction generator to 8 kVA transformer. Originality/value The paper presents the mitigation of grid transients during connection of induction generator with the power electronic converter working as reactive power compensator.


Author(s):  
Abedalgany Athamneh ◽  
Bilal Al Majali

<p><span lang="EN-US">A stable operation of wind turbines connected to the grid is an essential requirement to ensure the reliability and stability of the power system. To achieve such operational objective, installing static synchronous compensator static synchronous compensator (STATCOM) as a main compensation device guarantees the voltage stability enhancement of the wind farm connected to distribution network at different operating scenarios. STATCOM either supplies or absorbs reactive power in order to ensure the voltage profile within the standard-margins and to avoid turbine tripping, accordingly. This paper present new study that investigates the most suitable-location to install STATCOM in a distribution system connected wind farm to maintain the voltage-levels within the stability margins. For a large-scale squirrel cage induction generator squirrel-cage induction generator (SCIG-based) wind turbine system, the impact of STATCOM installation was tested in different places and voltage-levels in the distribution system. The proposed method effectiveness in enhancing the voltage profile and balancing the reactive power is validated, the results were repeated for different scenarios of expected contingencies. The voltage profile, power flow, and reactive power balance of the distribution system are observed using MATLAB/Simulink software. </span></p>


2012 ◽  
Vol 496 ◽  
pp. 104-108
Author(s):  
Bai Shan Mei ◽  
Han Kun Jiang ◽  
Jiang Yu

In this paper, a new control scheme of a variable speed grid connected wind energy generation system was presented. The scheme used a squirrel-cage induction generator (SCIG) as generator and it connected to the grid through a back-to-back double PWM converter. According to the characteristics of induction motor, the generator side adopted rotor flux linkage oriented slip frequency vector control technology, and the grid side used the network voltage oriented control and voltage and current dual close-loop control strategy. The simulation results show that the system can work in the state of variable speed constant frequency (VSCF)power generation and the active and reactive power can be controlled with no mutual interference and with good static-dynamic performance.


2021 ◽  
pp. 0309524X2110241
Author(s):  
Nindra Sekhar ◽  
Natarajan Kumaresan

To overcome the difficulties of extending the main power grid to isolated locations, this paper proposes the local installation of a combination of three renewable energy sources, namely, a wind driven DFIG, a solar PV unit, a biogas driven squirrel-cage induction generator (SCIG), and an energy storage battery system. In this configuration one bi-directional SPWM inverter at the rotor side of the DFIG controls the voltage and frequency, to maintain them constant on its stator side, which feeds the load. The PV-battery also supplies the load, through another inverter and a hysteresis controller. Appropriately adding a capacitor bank and a DSTATCOM has also been considered, to share the reactive power requirement of the system. Performance of various modes of operation of this coordinated scheme has been studied through simulation. All the results and relevant waveforms are presented and discussed to validate the successful working of the proposed system.


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