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The ac and dc electric field meters developed for the US Department of Energy
Two space-potential electric field meters developed at the Jet Propulsion Laboratory under the auspices of the U.S. Department of Energy are described. One of the meters was designed to measure dc fields, the other ac fields. Both meters use fiber optics to couple a small measuring probe to a remote readout device, so as to minimize field perturbation due to the presence of the probe. By using coherent detection, it has been possible to produce instruments whose operating range extends from about 10 V/m up to about 2.5 kV/cm, without the need for range switching on the probe. The electrical and mechanical design of both meters are described in detail. Data from laboratory tests are presented, as well as the results of the tests at the National Bureau of Standards and the Electric Power Research Institute's High Voltage Transmission Research Facility.
dc electric field meter with fiber-optic readout
The design of a dc electric field meter capable of measuring the magnitude and direction of the electric field at an arbitrary location above the ground plane is described. The meter is based on measuring induced charge on a split cylindrical electrode pair which is rotated around its axis of symmetry. Data readout is by fiber-optic cable using pulse frequency encoding. The sensing head is electrically isolated. Initial results are reported from a series of tests at General Electric's High Voltage Transmission Research Facility, Pittsfield, MA. The electric field was measured in a large test cage and under a dc test line. Measurement of field magnitude and direction around a human subject standing under the conductor was demonstrated.
Low-rate gas flow meter.
Low rate gas flow meter noting sealing and controlling of piston, differential pressure meter and DC servoamplifier
Instrumentation for Assessing DC Electrical Distribution Systems in Buildings
Direct current (DC) distribution systems is emerging as a favorable option over alternating current in buildings due to its energy and non-energy benefits (e.g., efficiency, resilience, safety). However, limited guidelines exist to evaluate the DC electrical distribution infrastructure. This paper aims to fill that gap by detailing our experience with metering a building-level electrical DC distribution system. Our case study is a DC microgrid at the Direct Energy Partners Research & Development facility located in Charlotte, North Carolina. This paper presents our approach, technical challenges, and lessons learned with DC metering and instrumentation.
Rectenna Technology Program: Ultra light 2.45 GHz rectenna 20 GHz rectenna
The program had two general objectives. The first objective was to develop the two plane rectenna format for space application at 2.45 GHz. The resultant foreplane was a thin-film, etched-circuit format fabricated from a laminate composed of 2 mil Kapton F sandwiched between sheets of 1 oz copper. The thin-film foreplane contains half wave dipoles, filter circuits, rectifying Schottky diode, and dc bussing lead. It weighs 160 grams per square meter. Efficiency and dc power output density were measured at 85% and 1 kw/sq m, respectively. Special testing techniques to measure temperature of circuit and diode without perturbing microwave operation using the fluoroptic thermometer were developed. A second objective was to investigate rectenna technology for use at 20 GHz and higher frequencies. Several fabrication formats including the thin-film scaled from 2.45 GHz, ceramic substrate and silk-screening, and monolithic were investigated, with the conclusion that the monolithic approach was the best. A preliminary design of the monolithic rectenna structure and the integrated Schottky diode were made.
Python Measurement-Informed Modelling Method (PythonMIMM) v1.02
This Python program implements the calculations for electrical energy efficiency and electrical losses in the paper "Energy and power quality measurement for electrical distribution in AC and DC microgrid buildings" (https://www.sciencedirect.com/science/article/abs/pii/S0306261921015658). The inputs are metered voltage, current, or power data of meters located throughout the DC system. In the absence of metered data, the user must input some other information about the building such as the types of power converters or wire lengths. The program will build a loss model of the DC system based on metered data and electrical information. It will also generate an equivalent AC system and determine the losses and efficiency.
Dynamic characteristics of a 20 kHz resonant power system - Fault identification and fault recovery
A detailed simulation of a dc inductor resonant driver and receiver is used to demonstrate the transient characteristics of a 20 kHz resonant power system during fault and overload conditions. The simulated system consists of a dc inductor resonant inverter (driver), a 50-meter transmission cable, and a dc inductor resonant receiver load. Of particular interest are the driver and receiver performance during fault and overload conditions and on the recovery characteristics following removal of the fault. The information gained from these studies sets the stage for further work in fault identification and autonomous power system control.
Development of a capacitance measurement for pulsed magnetic fields
Capacitance measurements are crucial for probing the electrical properties of materials. In this study, we develop and implement a capacitance measurement technique optimized for pulsed magnetic fields. Our approach employs an auto-balancing bridge method, leveraging a high-bandwidth transimpedance amplifier to mitigate parasitic contributions from coaxial cables. This technique enables precise capacitance measurements in rapidly changing magnetic fields, as demonstrated in experiments on the magnetoelectric material NiCo 2 TeO 6 . The results reveal strong magnetoelectric coupling, including a pronounced hysteresis in capacitance that coincides with magnetization measurements and an enhanced energy dissipation peak at high sweep rates. Compared to traditional LCR meter measurements in DC fields, our method exhibits excellent agreement while providing additional insight into field-induced phase transitions. This work establishes a robust methodology for capacitance measurements under extreme conditions and opens new opportunities for studying multiferroic and correlated electron systems under high magnetic fields.
Improved RF calibration techniques - dc potentiometer microwave insertion loss test set
Dual-channel microwave insertion loss test set which incorporates power meter coaxial thermistors with dc nulling scheme
Magnetic and electric field meters developed for the US Department of Energy
This report describes work done at the Jet Propulsion Laboratory for the Office of Energy Storage and Distribution of DOE on the measurement of power line fields. A magnetic field meter is discussed that uses fiber optics to couple a small measuring probe to a remote readout device. The use of fiber optics minimizes electric field perturbation due to the presence of the probe and provides electric isolation for the probe, so that it could be used in a high field or high voltage environment. Power to operate the sensor electronics is transferred via an optical fiber, and converted to electrical form by a small photodiode array. The fundamental, the second and third harmonics of the field are filtered and separately measured, as well as the broadband rms level of the field. The design of the meter is described in detail and data from laboratory tests are presented. The report also describes work done to improve the performance of a DC bushing in a Swedish factory, using the improved meter. The DC electric fields are measured with synchronous detection to provide field magnitude data in two component directions.
Thin-film power-density meter for millimeter wavelengths
A quasi-optical power density meter for millimeter and submillimeter wavelengths has been developed. The device is a 2-cm2 thin-film bismuth bolometer deposited on a mylar membrane. The resistance responsivity is 150 Ohms/W, and the time constant is 1 min. The meter is calibrated at DC. The bolometer is much thinner than a wavelength, and can thus be modeled as a lumped resistance in a transmission-line equivalent circuit. The absorption coefficient is 0.5 for 189-Ohms/square film. The power-density meter has been used to measure absolute power densities for millimeter-wave antenna efficiency measurements. Absolute power densities of 0.5 mW/sq cm have been measured to an estimated accuracy of 5 percent.
Anti-Adhesion Elastomer Seal Coatings for Ultraviolet and Atomic Oxygen Protection
Radiation blocking sunscreen coatings have been developed for the protection of elastomer seals used in low-Earth-orbit (LEO). The coatings protect the seals from ultraviolet (UV) radiation and atomic oxygen (AO) damage. The coatings were developed for use on NASA docking seals. Docking seal damage from the UV and AO present in LEO can constrain mission time-line, flight mode options, and increases risk. A low level of adhesion is also required for docking seals so undocking push-off forces can be low. The coatings presented also mitigate this unwanted adhesion. Greases with low collected volatile condensable materials (CVCM) and low total mass loss (TML) were mixed with slippery and/or UV blocking powders to create the protective coatings. Coatings were applied at rates up to 2 milligrams per square centimeter. Coated seals were exposed to AO and UV in the NUV (near-UV) and UV-C wavelength ranges (300 to 400 nanometers and 254 nanometers, respectively). Ground based ashers were used to simulate the AO of space. The Sun's UV energy was mimicked assuming a nose forward flight mode, resulting in an exposure rate of 2.5 megajoules per square meter per day. Exposures between 0 and 147 megajoules per square meter (UV-C) and 245 megajoules per square meter (NUV) were accomplished. The protective coatings were durable, providing protection from UV after a simulated docking and undocking cycle. The level of protection begins to decline at coverage rates less than 0.9 milligrams per square centimeter. The leakage of seals coated with Braycote plus 20 percent Z-cote ZnO sunscreen increased by a factor of 40 after moderate AO exposure; indicating that this coating might not be suitable due to AO intolerance. Seals coated with DC-7-16.4 percent Z-cote ZnO sunscreen were not significantly affected by combined doses of 2 x 10 (sup 21) atoms per square AO with 73 megajoules per square meter UV-C. Unprotected seals were significantly damaged at UV-C exposures of 0.3 megajoules per square meter and DC-7-16.4 percent Z-cote coated seals were undamaged at all exposures up to the limits tested thus far which were 147 megajoules per square meter UV-C and 245 megajoules per square meter NUV. The coatings decreased adhesion sufficiently for docking seals at temperatures equal to or greater than -8 degrees Centigrade thus offer a simple and inexpensive way to mitigate adhesion.
Modeling and Analysis of Clean Energy and Storage Technologies (CRADA Final Report, Project 1)
The goal of this project is to provide Southern Company Services, Inc. ("Participant") with custom scripts that can be used to create an average PV energy production profile, calculate lifetime energy value, calculate capacity value, and calculate the resultant financial metrics considering those value streams. Secondly, a fuel-cell model will be added to the public version of System Advisor Model (SAM). This standalone technology will incorporate PV and battery storage, allowing the participant to model the interaction of these three technologies. By adding this capability to a public version of SAM, a broad audience will be able to consider the system performance and financial benefits of installing a fuel cell as a baseline generator with PV. Thirdly, automated dispatch algorithms will be developed and added to SAM. These algorithms will enable Southern Company to dispatch a DC-connected front-of-the-meter battery system while considering price signals and PV clipping behavior. By adding these capabilities to a public version of SAM, users will be able to consider more complex and realistic ways of dispatching a battery system.
Cost analysis of distributed storage in AC and DC microgrids
Building and microgrid designs with highly-distributed electrical storage have potential advantages over today's conventional topologies with centralized storage. Herein this paper studies the capital cost benefits of several residential behind-the-meter distributed-storage topologies, including AC and DC versions of systems with load-packaged batteries and resilient sub-networks. The study begins by defining the block configuration of each topology. This work then develops a model for the cost of the power electronics necessary to interface with the storage elements. Finally, the analysis develops a model for the total cost of each storage topology, incorporating the installation and soft costs. The results suggest that while the cost of power electronics is lower in centralized topologies, the total cost is lower for distributed storage due to the avoided costs of installation and permitting. This paper also explores the benefits of load-packaged batteries for savings in electrical infrastructure.
Computer modeling and simulation of a 20kHz ac distribution system for Space Station
A computer model of a 20 kHz, ac distribution testbed for Space Station is presented. The system consists of six resonant inverters, a one-hundred-meter transmission line, and three load receivers: a dc receiver, a bidirectional receiver, and an ac receiver. A model library is generated characterizing all system components. The system's local and global behaviors are investigated using the EASY5 dynamic analysis program.
The evaluation of a metered mixer for RTV silicone for RSRM nozzle backfill operations
Metered mixing specifically for the RSRM backfill operation was investigated. Projected advantages were the elimination of waste RTV silicone produced in the operation and the elimination of entrapped air during the mix. Although metered mixing proved to be a viable method for mixing the Dow Corning DC 90-0006 rubber with its catalyst, applying the technology to the RSRM backfill operation has several disadvantages that are decisive. Use of a metered mixer would increase the amount of material that was being scraped for each backfill and increase the amount of time required to clean up the equipment after each operation. Therefore, use of metered static mixers is not recommended for use in the RSRM nozzle backfill operations. Because metered mixers proved to have significant disadvantages other methods of mixing and dispensing the RTV during the backfill operation are being investigated, and will be reported in a separate document.