ABSTRACT:
The smart grid system is an ideal solution to overcome the limitations of traditional grid systems. A system is considered smart if it has smart in all its parts such as smart generation, smart transmission and distribution, smart control, smart metering, and . . . etc. In this paper, smart transmission and distribution have been presented to achieve the requirements of the smart grid system. By transferring to the smart grid, all utilities catch a lot of benefits such as increasing reliability, efficiency, and safety. On other hand, the operation cost will be decreased. In addition, fast dynamic response for fault detection and isolation based on automatic Internet of Things (IoT) and wireless control can be achieved. It should be noted that in the smart grids, the security of the system and occupational safety will be greatly increased. The system has been validated under different kinds of faults such as single-line to ground fault, and double-line to ground fault.The simulation work is carried out using MATLAB/SIMULINK.

INTRODUCTION:

The electrical systems became complex and contained many components, which was due to the increasing demand for energy, which led to an increase in generation stations and thus increase the need to develop and raise the efficiency of transmission and distribution systems. These traditional systems suffer from many problems related to the system’s ability to restore its stability after any kind of fault occurs. Recently, many researchers and large companies have turned to using modern systems in controlling all components of the system, and the system has been called the smart grid. The use of a smart grid allowed reliability, security, demand side management system, metering, self-healing, connection with micro-grids, and integration of renewable resources. The system can be called smart if one part or all parts of it became smart and the parts are generation, transmission, distribution, control, and metering. New smart grid monitoring has been used which led to develop and increase the electric utility, three-step control has been presented to optimize the overall efficiency in the automatic solving of the energy fluctuations has been presented in addition, the effect of smart grid on the physical power grid has been analyzed, in the effects of smart grid on the national grids have been proposed. besides, it presented several effective proposals to transform the traditional grid into a smart grid. in a smart grid model has been presented and it discusses the benefit of a smart grid for the long term, only the smart generation is interested has been presented. In this paper, the smart transmission and distribution system has been presented under different faults to achieve the requirements of smart grid systems. It is worth mentioning that all kinds of faults have a direct effect on the power system generation, hence the smart grid has been proposed to give a good solution for the system under faults, in addition, the system has a good dynamic response under the dynamic change of the system wither was a fault or load change. A lot of electrical systems have been studied based on different faults. The effective algorithms have been presented to locate the fault for the two-parallel transmission line. The behavior of the system voltage and load currents have been studied based on different faults with linear and non-linear loads, a novel method of the single-phase-to-ground fault has been presented. A double line to the ground has been applied, in addition, Fault resistance values are determined, The tripping of the line without fault has been discussed and this tripping is more dangerous than a three-phase permanent ground fault, the criterion used in this previous study showed that the inertia time constants, transfer impedance angle and initial relative phase angle between two machines are the important items to determine any machines most effected by fault. The faults in the transmission and distribution system can be solved by different methods like the fault current limiter which improve the transient stability of a grid and the (FRT) by using the proposed shunt resonance fault current limiter. And crowbar resistance. The influence of crowbar resistance on the stability of DFIG with (FRT) has been presented. The crowbar has been designed to the grid voltage dip to limit rotor fault current, DC-link over-voltage, and protect the rotor converter effectively. The maximum crowbar resistance has been used to protect the over-voltage of the rotor side converter from high rotor currents, and also avoid high currents flowing through the rotor side converter to the DC-link capacitor. The influence of various types of faults on grid-connected with (DFIG WECS) with and without crowbar resistance has been presented. The study the crowbar protection system has been presented. In addition, the crowbar resistance value is calculated. All previous techniques for using crowbars used the traditional method to allow the crowbar to catch in the system which depends on the manual adjustable of the time that the crowbar works as a protection device. Some papers put a control system to the electronic switches of the crowbar system to catch in and out from the grid automatically. Presents different control strategies of the crowbar protection used with DFIM during a voltage dip in the grid. Grid faults used a designed (ANFIS) crowbar protection strategy for DFIG. Proposed a novel controllable (CBFT) protection technique for DFIG WECS connected to the grid. For the problem in rotor current and DC bus voltage in DFIG showing adaptive control strategy and the resistance setting method, With the proposed scheme both the rotor current and DC-bus voltage can be controlled inside the restriction. Self-controllable crowbar is proposed to improve the reliability of the BDFRG under faults. A hybrid fuzzy-PI controller to create a control signal for an electronic switch(IGBT) of the crowbar system.
PROBLEM STATEMENT
In this, a new control strategy for the crowbar has been used which the crowbar has been automatically catching in and out of the system without any manual adjustable. In addition, the system used was wind only. in this paper, the control strategy used has been modified to be suitable for a smart generation system, and the main motivation in this paper can be summarized as: • Convert the traditional transmission and distribution system to a smart system by using a simple controllable crowbar simple with self-hailing. • Using controllable crowbar not only with wind generation but also with hybrid generation.