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چكيده انگليسي :

۱۱۳ Distributed Networked Control of Load Frequency in Multi area Interconnected Power System Hamid Zamanian h zamanian@ec iut ac ir Date of Submission 10 19 2014 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor J Ghaisari ghaisari@cc iut ac ir F Sheikholeslam sheikh@cc iut ac irAdvisor M A Latify latify@cc iut ac irAbstract Due to the increasing of complexity in power systems restructuring of power system and innovativemovements toward smart grids it is developing to use of communication networks as the base of datatransmitting The variety of advances of NCS systems causes their usage in power systems as a necessity One of the applicative fields of NCS in power systems is to support of ancillary services such as load frequency control LFC in deregulated environment Frequency control as a major function of automaticgeneration control AGC has been one of the important control problems in design and performance ofelectric power systems In a multi area interconnected power system AGC systems are designed andimplemented to a group of power plant Maintain frequency and power interchange with neighboring controlareas at scheduled value are the two main objectives of an AGC system Receiving signal of control areasand transmitting AGC control signals is done by using of communication network One of the challenges incommunication networks is the communication delay in sending or receiving control signals It is wellknown that time delays can degrade on performance of LFC system and even cause system instability In thisthesis at first we sought to investigate the degree of interaction and dependency between control area inmulti area power system This investigation is done based on gershgorin bonds This results show thatinteraction between area is considerable So it is expected that by using of distributed control structure wecan improve the control performance of AGC system In following two new methods are presented fordesigning a robust controller based on distributed control structure for AGC systems In the first method theinteraction effect between control area in multi area power system is considered as input in state equation ofeach control area In this way control effort is proposed for each area so that they have knowledge abouttheir states of neighbor control area besides their ownself Therefore controller can do its duty with moreinformation and get to more improvement and system performance In the second the effect of interaction isconsidered as disturbance The proposed control structure of this method is so that by entering the upperbands of delay in each step of design and considering the appropriate weight matrices besides of lowerconservativeness it shows more robust performance versus other controllers To investigating theperformance of proposed control strategies several simulations are done on three area LFC schemes undertraditional and deregulated environments These simulations have been done on different scenarios and incomparing with different papers discussed on this field The results show that proposed strategy can followthe load variations as well and restores the frequency deviations and power interchange with neighboringcontrol areas to nominal and scheduled by considering communication delay Although the presented controlgains of other references can not sustain the stability of system in presence of time varying delay Keywords Multi area interconnected power system Networked Control System NCS Load FrequencyControl LFC Automatic Generation Control AGC Time delay Distributed control

زمانيان، حميد

كنترل توزيع شده ي بار- فركانس تحت شبكه در سيستم قدرت چند ناحيه اي بهم پيوسته

سيستم كنترل تحت شبكه ﴿NCS﴾ , سيستم كنترل بار- فركانس ﴿LFC﴾ , سيستم كنترل توليد خودكار ﴿AGC﴾ , كنترل توزيع شده