Table of ContentsIntroductionInverter ParametersCable ParametersMotor ParametersLiterature SurveyIntroductionElectricity is the backbone of our existence in the world of Today. It is quite difficult to imagine a world without electricity in modern times. We depend on it for much of our daily activities. However, electricity does not exist in its natural form nor can it be stored in large quantities. It must be operated from renewable or non-renewable resources and must be continuously generated to meet consumer demand. The electricity generated from its various sources is delivered to end users/consumers through transmission and distribution (T&D) lines. Say no to plagiarism. Get a tailor-made essay on “Why violent video games should not be banned”?Get the original essayTransmission lines consist of wires/cables hung from tall metal towers and carry electricity over long distances at high tension. Electricity produced at power plants travels through this complex system, often called a "grid," which includes power lines, transformers, and power substations that ultimately connect electricity producers to consumers. The smart grid is a recent development in transportation and distribution networks. A smart grid enhances the traditional transmission and distribution system through the use of digital technology and advanced instrumentation that allows utilities and customers to receive up-to-date information from the grid and also allows communication with the grid . The grid is termed smarter because it makes the T&D power system more reliable and also more efficient in reducing transmission losses and allows utilities to quickly detect and resolve problems. The smart grid also allows end users to intelligently manage electricity consumption, especially during times of high demand or when system reliability requires lower energy demand. High-voltage electricity is used in long-distance electricity transmission because it is associated with low currents and reduces transmission losses, and therefore more efficient and less expensive than low-voltage transmission. However, low voltage electricity is required in homes and businesses viz. end users. Transformers located at different stages of the network and in substations carry out the work of increasing (increasing) or reducing (decreasing) electrical voltages to accommodate different stages of the movement of electricity, from the source of the power plants to long journeys. distance transmission lines and low-voltage distribution lines that carry electricity to homes and businesses. The transformer consists of a set of 2 coils (3 coils for a three-phase system), tightly coupled by means of a magnetic core. Developments in power electronics technology have improved the switching frequency of devices. Insulated gate bipolar transistor (IGBT) technology is currently capable of switching frequencies between 10 and 20 kHz, as well as rise times of 0.1 µs[1]. The performance of the PWM (Pulse Width Modulation) voltage inverter is also as its output waveform has improved significantly with this development, making it the popular choice for power drives.variable speed induction motors. The induction motor and PWM inverter are mostly located in different locations, especially in industrial applications, and therefore require long cables or motor cables. Figure 1 shows a practical connection of an induction motor powered via a PWM inverter using a long cable. Electromagnetic pulses propagate at half the speed of light (3*108 m/s), or approximately (150-200 m/µs). If the electromagnetic pulses take more than half the rise time to travel from the drive output to the motor, a complete reflection of the pulse will occur at the motor terminal. This will cause the amplitude of the voltage pulse to double. Increasing the rise time and fall time of the inverter's voltage output pulses will help reduce this pulse reflection caused by fast switching transients. Factors affecting voltage reflection are the rise time of the inverter output voltage pulses, tp the length of the cable used to connect the inverter and the motor, which affects the propagation time, tp of the pulse Impedance of cable and motor overvoltageIf tp>tr/2, then a complete reflection of the pulse occurs and causes a doubling of the voltage amplitude at the motor terminal [1] [2]. To reduce the dv/dt gradient of the inverter output voltage, a passive dv/dt filter with inductor, capacitor and resistor can be used. . The major disadvantage of these filters is the significant power loss. The reflected voltage amplitude depends on the voltage reflection coefficient (ℾm) of the motor and is given by the equation below: ℾm = Zm-Zc/Zm+Zc where Zm is the characteristic impedance of the motor and Zc is the characteristic impedance of the cable. The peak voltage at the motor terminal (Vm) is given by the following equation, Vm=Vs(1+ ℾm) where Vs represents the source voltage. The reflection coefficient varies with motor size and its value decreases as motor size increases. To reduce losses in the induction motor, fast switching devices are used in the inverter, but this in turn can cause an overvoltage to appear at the motor terminals. A shorter rise time or steep voltage slope would cause motor insulation to break down. J Desmat et al [6] studied and analyzed the impact of the following parameters on the overvoltage at the motor terminals Inverter parameters The influence of carrier frequency, voltage rise and U/fa characteristics was analyzed. No surge or slope differences were detected when using a carrier frequency of 2, 5, 8, 12, or 16 kHz. But increasing the frequency leads to an increase in the number of surges per unit time. Changing the motor frequencies to 10, 30, 50, 60, and 70 Hz also did not cause a surge. However, the number of surges per unit time increases with increasing motor frequency. Additionally, the starting voltage had no impact on the surge. The U/f characteristics have the same effect on overvoltage as the carrier frequency and motor frequency. Cable parameters The influence of cable length, cable type and cross section was analyzed. Motor voltage slope and increase as cable length increases. The difference in cable composition affects damping. Increasing the cross section of the cable increases the voltage slope across the motor terminals. Motor parameters Motor power has a slight impact on the motor reflection coefficient. For a motor power lower than 22 kW, this effect is not visible. It was observed that certain parameters such as the rise time of thevoltage at the inverter, the length, section and type of cable, the motor power and the frequency of the inverter carrier wave have a significant impact on the appearance of overvoltages. on the engine side. The project aims to implement a state-of-the-art surge forecasting system using AI techniques. The test system consists of a motor driven by a PWM inverter circuit via long wires or cables. Knowing the peak surge is important for coordinating the insulation of long cables. The power parameters and cable parameters are intended to be transmitted to the proposed system to provide an estimate of the surge value. Literature Review Many researchers have worked on the topic of overvoltage in transmission lines. Some research focuses on surges in power lines and others focuses on surges on motors connected via long cables on inverter-powered systems. Researchers have identified the factors causing power surges. Solutions based on artificial neural networks (ANN) are proposed by few researchers to predict surges on power lines [1][2]. Support vector machine (SVM) based classification of induction motor supply voltage has also been explored by researchers [7] in the past. AV Jouanne et et al. [1] examines the duration of motor cables that affect AC motor drives powered by high-frequency PWM inverters. It is observed that although high switching speed leads to improvement in the performance parameters of PWM inverters, it has a negative effect on motor insulation. Additionally, a long cable length tends to cause an overvoltage at the motor terminals, which puts additional strain on the motor insulation. Voltage reflection is analyzed/studied and cable transmission theory and cable capacitance analysis are presented. The paper also illustrates how the cable length and rise time of the inverter's pulse output affect the magnitude of the voltage across the motor. A. Acharya B et et al. [2] designed specifically for motor drives with a dv/dt output filter. The paper proposed a new procedure to design an LC clamp filter. The output voltage of PWM inverters has high dv/dt, which can cause doubling of the peak voltage at the motor terminal connected using long cables. By using the proposed filter, the phenomenon of voltage doubling across the motor terminals can be reduced. There are several mitigation techniques available that can be implemented on the engine side. This involves the use of an insulated bearing, the use of an electrostatic shield between the rotor and the stator, an increase in the degree of insulation as well as a termination which corresponds to the impedance of the cable and the motor terminal. On the inverter side, the mitigation techniques that can be adopted are the use of a filter, common mode voltage reduction, and a resonant switching inverter. The proposed filter is aimed at components which are common mode or differential mode. Additionally, in the filter, the resonant frequency is selected, which causes the induction motor to behave like a high-frequency inductive load, which in turn has the LCL effect of a higher order filter . . The effectiveness of this is verified using the Pspice simulation. The filter is designed to be compact and can be easily included/placed throughout the inverter assembly. Vitor F. Couto et et al. [3] proposes an alternative strategy for modeling a transmission line that analyzes the three phase conductors.