Strategies Regarding Operating Voltage Levels in Distribution Networks

The power/energy losses reduction in distribution systems is an important issue during planning and operation, with important technical and economical implications. Thus, the energy losses minimization implies not only the technical improvement of the network, through its renewal with the introduction of the technological innovations in the equipment and circuit components as well as the optimal planning of the design and development of the network, but also requires the use of the methods and software tools to facilitate the operation process. The paper presents a strategy for power / energy saving which is replacement of the 6 kV voltage level with 20 kV voltage level. In this line, different urban distribution networks were analyzed using fuzzy techniques for load modeling.

Adaptive Sub-Threshold Voltage Level Control for Voltage Deviate-Domino Circuits

Leakage power and propagation delay are two significant issues found in sub-micron technology-based Complementary Metal-Oxide-Semiconductor(CMOS)-based Very Large-Scale Integration(VLSI)circuit designs.Positive Channel Metal Oxide Semiconductor(PMOS)has been replaced by Negative Channel Metal Oxide Semiconductor(NMOS)in recent years,with low dimen-sion-switching changes in order to shape the mirror of voltage comparator.NMOS is used to reduce stacking leakage as well as total exchange.Domino Logic Cir-cuit is a powerful and versatile digital programmer that gained popularity in recent years.In this study regarding Adaptive Sub Threshold Voltage Level Control Pro-blem,the researchers intend to solve the contention issues,reduce power dissipa-tion,and increase the noise immunity by proposing Adaptive Sub Threshold Voltage Level Control(ASVLC)-based domino circuit.The efficiency and effec-tiveness of the domino circuit are demonstrated through simulation results.The suggested system makes use of high-speed broad fan-gate circuits,occupies mini-mum space,and consumes meagre amount of power.The proposed circuit was validated in Cadence simulation tool at a supply voltage of 1V,frequency of 100 MHz,and an operating temperature of 27°C with 64 input OR gates.As per the simulation results,the suggested Domino Gate reduced the power dissipa-tion by 17.58 percent and improved the noise immunity by 1.21 times in compar-ison with standard domino logic circuits.

Integrated Approach to the Formation of Service Areas for Urban Substations of Different Voltage

UPSS （urban power supply system） is a part of the region or the state power supply system. UPSS development is closely connected with region power supply system development as a whole. The decision of questions of long-term and middle-term planning of UPSS development occurs in the conditions of incompleteness and uncertainty of the initial information. Nevertheless in these conditions the acceptance of development strategy should be based on perspective electric loads of urban TS （transformer substations）. There are difficulties with a rational placement of substations in the city with the developed infrastructure. Such problem by theoretically grounded approach to rational formation of UPSS is solved. The hierarchical structure of the organizational construction, voltage levels and load densities is considered. The mathematical and geometrical modeling of service areas for transformer substations of different voltage is fulfilled. The method of graphic placement of transformer substations in the city territory for new substations at existing structure of networks is offered. The aim of the work is to present the new uniform approach which allows finding a rational decision for new substations＇ placement in cities with developed infrastructure on the beginning design stages in conditions of the information uncertainty. The calculation program Microsoft EXCEL and the graphic program AutoCAD are used for realization of method.

Monolithically integrated enhancement/depletion-mode Al Ga N/Ga N HEMTs SRAM unit and voltage level shifter using fluorine plasma treatment

A GaN-based E/D mode direct-couple logic 6 transistors SRAM unit and a voltage level shifter were designed and fabricated. E-mode and D-mode A1GaN/GaN HEMTs were integrated in one wafer using fluorine plasma treatment and using a moderate A1GaN barrier layer heterojunction structure. The 6 transistors SRAM unit consists of two symmetrical E/D mode inverters and two E-mode switch HEMTs. The output low and high voltage of the SRAM unit are 0.95 and 0.07 V at a voltage supply of 1 V. The voltage level shifter lowers the supply voltage using four Ni-A1GaN Schottky diodes in a series at a positive supply voltage of 6 V and a negative supply voltage of-6 V. By controlling the states of inverter modules of the level shifter in turn, the level shifter offers two channel voltage outputs of-0.5 and-5 V. The flip voltage of the level shifter is 0.76 V. Both the SRAM unit and voltage shifter operate correctly, demonstrating the promising potential for GaN-based E/D mode digital and analog integrated circuits. Several considerations are proposed to avoid the influence of threshold voltage degradation of D-mode and E-mode HEMT on the operation of the circuit.

Design of Power Supply Network Based on 500/110 kV for Load Center and Comprehensive Accessibility Evaluation

Growing electric power demand and the consumption of large-scale renewable energy require a more efficient power supply network,with less occupied areas in load centers.In this paper,application principles of power supply network based on 500/110 kV direct transformation are proposed.An in-depth analysis of the grid structure and substation design is presented along with an application scenario.An accessibility index based on power flow tracing for network evaluation is also proposed.The index is able to present the inner connectivity and power transferability of a power network.A comprehensive evaluation of traditional short circuit,load flow,N-1,economic calculation,and the accessibility index are conducted on the power grid planning of a high-tech industrial park in Wuhan,China.Finally,electric feasibility and reliability are validated,and accessibility and construction investments compared.