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Hardware for Distribution Systems
Published in James Northcote-Green, Robert Wilson, Control and Automation of Electrical Power Distribution Systems, 2017
James Northcote-Green, Robert Wilson
A voltage transformer is an instrument transformer in which the secondary voltage, in normal conditions of use, is substantially proportional to the primary voltage and differs in phase from it by an angle which is approximately zero for the appropriate direction of the connections. VTs are defined according to IEC 60044 Part 2.
Field test of in-situ conversion of coal
Published in International Journal of Coal Preparation and Utilization, 2022
Sergey M. Martemyanov, Andrey A. Bukharkin, Bolat T. Ermagambet, Zhanar M. Kasenova
The equipment receives power from a three-phase AC 380 V voltage source where the maximum current on each phase is at least 300 A. The unit is powered through Switch 3. When the switch is turned on, the power line voltage is fed to a high-current regulator, which provides for the smooth adjustment of the output voltage in the range between 20 to 250 V. The regulator can work as an independent high-current section, providing for the supply of a high current to the electrodes during the heating stage. At the stage of operating high-voltage or the intermediate section, the regulator allows for adjusting the supply voltage of these units. Therefore, this allows the operator to adjust the output voltage in any operating mode. The high-voltage transformer and intermediate section transformer receive power through switches 1 and 2, respectively, which makes it possible to disconnect devices that are not currently in use. The control unit controls switches 1, 2, and 3 displays the voltage and current values (Fig. 3a). Three-pole contactors with a rated current of 630 A and a voltage of 380 V are used as switches. All the contactors are mounted in a metal cabinet (Fig. 3b).
Highly Available Nuclear Power in a Microgrid Configuration for the ORNL Distribution System
Published in Nuclear Technology, 2022
Based on the results of Sensitivity 1, the base case analysis modeling is judged to be conservative. While the unavailability of both options is reduced compared to the base analysis, the sensitivity results are well within the uncertainty of the base analysis. The IEEE Standard 493-2007 buried cable failure rate of one failure every 2 years is expected to be conservative for the hardened underground line. However, this sensitivity suggests that the low-voltage circuit breaker data in the options 1 and 2 base analyses may not be an appropriate substitute for high-voltage circuit breakers. Additionally, the low-voltage transformer data in the option 2 base analysis are potentially nonconservative because high-voltage transformers are generally custom designed and more difficult to quickly repair or replace than low-voltage transformers.
EPE-Based Pilot Relaying Scheme Immune to SIR Variations
Published in IETE Journal of Research, 2020
To test the capability of proposed pilot relaying scheme, digital simulations using EMTDC/PSCAD [18] have been carried out and results are obtained. The equivalent diagram of power system with series compensation in line-B is depicted in Figure 4. Three different power system test models are used to verify the proposed scheme. The model data and TL data are given in Tables 1 and 2, respectively. The model-3 is nothing but the uncompensated version of model-1. The performance of proposed pilot relaying scheme has been investigated for different conditions. A capacitor voltage transformer is used with a ratio of 400 kV/100 V. The ratio of current transformer (CT) is 2400A/1A. All the phasors of voltages and currents have been calculated using FFT block of power system computer aided design/electromagnetic transient and DC library.