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Linear Graphs
Published in Clarence W. de Silva, Modeling of Dynamic Systems with Engineering Applications, 2023
As shown in Figure 5.6c, an electrical transformer has a primary coil, which is energized by an alternating-current (ac) voltage (vi), a secondary coil in which an ac voltage (vo) is induced, and a common core, which helps the linkage of magnetic flux between the two coils. A transformer converts vi to vo without making use of an external power source. Hence it is a passive device, just like a capacitor, inductor, or resistor. The parameter of the electrical transformer is the turn ratio: r=number of turns in the secondary coil(No)number of turns in the primary coil(Ni)
Autotransformers
Published in K.R.M. Nair, Power and Distribution Transformers, 2021
An autotransformer is a transformer in which at least two windings have a common part. In the electric power system, it finds application in place of a two-winding transformer, especially when the interconnection or power transfer is required between two high-voltage systems. The major advantages of an autotransformer are as follows; It has higher efficiency when compared to a two-winding transformer of equal rating.It has lower material cost.It offers better voltage regulation.The excitation current is low.
Electrical Power Systems/Improved Efficiency
Published in Dale R. Patrick, Stephen W. Fardo, Ray E. Richardson, Brian W. Fardo, Energy Conservation Guidebook, 2020
Dale R. Patrick, Stephen W. Fardo, Ray E. Richardson, Brian W. Fardo
Transformers are classified as step-up or step-down types. These types are illustrated in Figure 8-12. The step-up transformer has fewer turns of wire on the primary than on the secondary. If the primary winding has 1 00 turns of wire and the secondary has 1000 turns, a turns ratio of 1:10 is developed. Therefore, if 10 volts AC is applied to the primary from the source, 10 times that voltage, or 100 volts ac, will be transferred to the secondary circuit. A step-down transformer has more turns of wire on the primary than on the secondary. If the primary winding has 500 turns while the secondary winding has 50 turns, or a 10:1 ratio, and 120 volts AC is applied to the primary from the source, then one-tenth that amount, or 12 volts ac, will be transferred to the secondary circuit.
Optimization of Bio-based Liquid Transformer Insulator using MOORA Method
Published in Electric Power Components and Systems, 2020
Hemanth Gurumurthy, Suresha Bheemappa, Rudramuni Chidanandappa, Pradhyumna Bhat
Transformers are the devices that are utilized to step up or to step down the voltage in an electrical circuit based on the requirements. Three main parts of the transformer are the core, the primary winding, and the secondary winding. To step-up the voltage, the number of turns in the primary winding will be lesser than the number of turns in the secondary winding and vice versa. They work on Faraday's law of electromagnetic induction. The rate of magnetic flux change in the primary winding will induce the voltage in the secondary winding. During this process, there will be a loss of energy in the form of heat; hence there should be a medium to remove heat and avoid the short circuit between the primary and secondary windings. This medium is called as an Insulator. There are different types of electrical insulators. They are insulating oil, paper, wood, press boards made of fibers, polymers, and so on.
Design and Development of Industrial Energy Measurement Error Compensation Unit
Published in Electric Power Components and Systems, 2020
Makarand Sudhakar Ballal, Manish Ganesh Wath, Hiralal Murlidhar Suryawanshi
Instrument Transformers are in general are current transformers (CTs) and potential transformers (PTs) are extensively used in Industrial Energy Measurement System (IEMS). They are used for the measurement of electrical energy consumed by high-tension (HT) industrial consumers. Ratio and phase angle errors are the inherent characteristics of CTs and PTs. These errors are due to exciting current used for magnetizing the core of CTs and PTs and also because of the nonlinear behavior of this core under different system conditions [1]. These errors are responsible for inaccurate measurement of energy and thereby affect the revenue of power distribution utilities. Nowadays CTs and PTs of accuracy class 1.0, 0.5, and 0.2 are used for measurement and revenue [2]. Core material used for class 1.0 CTS and PTs is silicon steel. For 0.5 and 0.2 class of CTS and PTs, amorphous–nanocrystalline alloy is exclusively used. The processing and manufacturing cost of this alloy is very high. Hence, the cost of CTs and PTs increases with their class of accuracies as the cost of core material is substantially high [3].
Sensitivity analysis of a single phase to ground fault system in connection with high impedance faults: A case study
Published in Cogent Engineering, 2020
Perumal Velmurugan, Adhir Baran Chattopadhayay
In real-time measurements, instrument transformers are used to measure and analyze the primary voltages and currents safely. A current transformation ratio of 300/1 or 400/1 and a voltage transformation ratio of 11,000/110 are used in a medium-voltage distribution system. The neutral current transformation ratio of the station transformer (ST) is 1200/1 for a solidly earthed system. In the case of a high resistance/impedance grounded system, a current transformation of 30/1 or lower is used. Such a low transformation ratio is essential in the detection of low zero-sequence current produced by high impedance faults. The transformation of the primary-fault impedance “Zf” to secondary-fault impedance is calculated using the CT ratio and VT ratio. Later in this paper, the sensitivity of fault current to fault impedance is discussed. The sensitivity is a ratio and has no units. Therefore, CT and VT ratios do not affect the results of the sensitivity analysis.