E:  Mansoura Engineering Journal, (MEJ), Vol. 40, Issue 4: [the 8 th International Engineering Conference, December 2015, Part I] Accepted: 18 October  ATP-Based Fuzzy Logic Controller Model for Electromagnetic Transients Studies لكهرومغناطيسيتمج الظىاهر اهم في برنا المنطق المبتحكم نمىذج لم لعابرة ا Walaa El-Hadad and Ebrahim A. Badran   IEEE Member, Electrical Engineering Department, Mansoura University Mansoura, Egypt - email: ebadran@hotmail.com ملخص ال نعابشةطيسيت اايغشش انكاب انظايش حسايش بششة يخى حطد الخي في انعقATP ل خلش رنك يقذ ظ سخت انضشافيكيت انATP Draw ىبخحكى انيعخبش ان . Fuzzy رس حخاست انخي حغيش انخطي عقذةظى انخحكى ان احذ ايش. في انبشخذاييط لسخ بس نعابشةطيسيت اايغشش انكااست انظ نذسخذاي اسخك يانزي ىبطق انخحكى انرس ن زا انبحذ يقذو زيمقخشط يضعم حرس انان .ظى انق فيش بخلفايش يساعذ آخخذاو أي بش اسخى بسيط دبطق ان يخحكى ان ATP ال انذيي: حك رلد أصزاء يقخشط يخكرس انان . ت.بال انيم انذحت ، حنحاكاعذ ا ، انقرسان قخشط ان يتث انشقنحسابائش اخا ت بيقاسيذ حى انيت حل أيزهت سق خل يخباس حى اخنقذ أربخج .قخشطرس انئش انخا قخشط.رس انئش انخا دقت ت صحتقاس ان Abstract Alternative Transient Program (ATP) has been steadily developed and improved in the last decades. Today, ATP Draw, a graphical framework, is available, which has improved the use of the program significantly. However, fuzzy controller is one of complex models for which a simplified model can be a very useful tool. This paper introduces a model for fuzzy logic controller in ATP for electromagnetic transients' studies of power system. The proposed model introduces a first model of fuzzy logic in ATP. This facilitates power system and fuzzy logic controller simulation in ATP without needing any other programs. The proposed model is implemented in ATPDraw environment. The proposed fuzzy logic controller model consists of three parts; Membership functions (triangular and trapezoidal shapes), Rules and Defuzzification. The proposed model is verified using numerical examples. The membership degree, the rules, and the defuzzification are calculated using both numerical calculation and the proposed model. The proposed model verification shows acceptable results. Key words Fuzzy, AI, ATP, EMTP, Control, Electromagnetic Transients 1. Introduction Alternative Transient Program (ATP) has been steadily developed and improved in the last decades. Today ATP Draw [1], a graphical framework, is available, which has improved the use of the program significantly, above all for the less experienced users. However, many other resources are also available, but just waiting for improvements. Among those resources are the user specified models which allow for a more complex model to be modularized, making available just the essential information to the user [2]. Fuzzy controller is one of these complex models for which a simplified model can be a very useful tool in ATP Draw. For modeling the power system, control and interactions between them it can be chosen from among more options. First, an ATP [3, 4] code can be used to simulate the power system, and Transient Analysis of Control System (TACS), or to use the programming language MODELS in ATP. The main advantage of this approach is in simple interfacing between the power system and the control model