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Enhancing Smart Grid Resiliency
Published in Clark W. Gellings, Smart Grid Planning and Implementation, 2020
In 2011, two U.S. Department of Energy (DOE) projects demonstrated inverter products that can operate while tied to the grid or “islanded.” Princeton Power, Inc. (Princeton) demonstrated a 100-kW demand response inverter with two DC terminals and two AC terminals. Princeton is also introducing a 10-kW version specifically for the residential and small commercial markets. Petra Solar demonstrated a micro-inverter-based PV system capable of operating in grid-tie or islanded mode. Both companies report that they have demonstrated seamless transition between these modes. Other companies report development of similar products. With a proper transfer switch (perhaps controlled by the utility), these products could provide backup power to residences or a community during an outage.
The Earth Station
Published in Jerry D. Gibson, The Communications Handbook, 2018
One or more outboard engine generators may be used to supply primary or standby power. If a generator is planned, the required capacity should be calculated by determining the initial total site load and potential for growth. The maximum rate of fuel consumption per hour can then be calculated and a fuel storage tank can be sized accordingly. Consideration must be given to the placement of a fuel tank so that it remains accessible at all times for refueling. Local ordinances may stipulate whether the tank can be above or below ground and they will also dictate if special spill containment basins will be required. Newly installed underground tanks will require automatic leak detection systems and double-walled piping to comply with recent federal Environmental Protection Agency (EPA) rulings. As part of a standby generator system, an electrical or mechanical transfer switch will need to be installed. The transfer switch
Specific Maintenance Procedures and Requirements
Published in Ryan Cruzan, Manager’s Guide to Preventive Building Maintenance, 2020
Emergency generators provide their power to the building through a transfer switch which transfers the building from the electrical utility’s power lines and onto the emergency generator. Transfer switches are required to prevent the electricity from the generator from entering the power utility’s lines where it could injure or kill someone working on the electric lines. Most of these switches are automatic (Automatic Transfer Switches ATS) and will automatically start the generator and transfer power to the building within 10 seconds of a power interruption.
Reduced DC sensor based grid-interactive operation of single-stage solar photovoltaic water pumping system
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Rajan V. Vamja, Mahmadasraf A. Mulla
The system configuration of the proposed single-stage grid-interactive SPVWPS is as shown in Figure 1(d). The presented system is made up of an SPV array, three-phase voltage source inverter, transfer switch, induction motor, and the single-phase utility grid. Based on the requirements of the irrigation and accessibility of SPV power, the presented system functions in two possible modes as shown in Table 1. For standalone SPVWPS operation, the transfer switch remains open and disconnects the grid supply. For the grid-interactive operation, the transfer switch connects the single-phase utility grid between the star terminal of motor winding and mid terminal of the DC-bus. Only three sensors, i.e., two AC and one DC sensor, are utilized to implement the presented grid-interactive control scheme. The details of both operations are given in the following subsections.
Dual-panel liquid crystal displays with wide colour gamut and high luminance
Published in Liquid Crystals, 2021
Chi Zhang, Rui Niu, Xiaoshuai Li, Hongmei Ma, Yubao Sun
Figure 1 shows the structure diagram of the dual-panel LCD. The main panel and backlight unit are at the top and bottom side of the dual-panel LCD, respectively. The sub-panel is located between the main panel and backlight unit. The main panel is used for display function. Any type of LC panels can be used as the main panel, like 90° twisted nematic (TN) panel, vertical alignment (VA) panel, fringe-filed switching (FFS) panel, in-plane switching (IPS) panel, and et al, and we have used the FFS panel as the main panel in this paper. The sub-panel is used for mode transfer switch, so the arrangements of liquid crystal molecules in different driving states must be considered. In this paper, the TN panel is chosen as the sub-panel. A directional backlight is used as the backlight unit to improve the viewing angle. The Inverted Prism Film is used to confine the light in a small divergent angle (±20°), and the dual brightness enhancement film (DBEF) is used to improve the luminance. Compared to the normal LCD, there is only an additional sub-panel in the proposed dual-panel LCD.
On modelling of resiliency events using building performance simulation: a multi-objective approach
Published in Journal of Building Performance Simulation, 2022
Scott Bucking, Milad Rostami, Joshua Reinhart, Max St-Jacques
A microgrid compatible inverter and an automatic transfer switch allowed the home to disconnect from the grid and self-power during an outage. This configuration enabled the home to import and export electricity throughout the year while still maintaining off-grid capabilities. Microgrid compatible configurations do carry significant cost premiums. For this paper, it was assumed that PV was roof integrated (ie. replacing a finished surface) for $1.5/W and microgrid compatible components carried a 25% total cost premium (applied to PV, inverter and battery capital expenditures). The 21 kWh battery back was purchased for $9,000 CAD ($425/kWh). As microgrid compatible components become more common, this cost premium may decrease in the future.