Protocol for multiple node network

The invention is a multiple interconnected network of intelligent message-repeating remote nodes which employs an antibody recognition message termination process performed by all remote nodes and a remote node polling process performed by other nodes which are master units controlling remote nodes in respective zones of the network assigned to respective master nodes. Each remote node repeats only those messages originated in the local zone, to provide isolation among the master nodes

High speed polling protocol for multiple node network

The invention is a multiple interconnected network of intelligent message-repeating remote nodes which employs a remote node polling process performed by a master node by transmitting a polling message generically addressed to all remote nodes associated with the master node. Each remote node responds upon receipt of the generically addressed polling message by transmitting a poll-answering informational message and by relaying the polling message to other adjacent remote nodes

Rotationally Vibrating Electric-Field Mill

A proposed instrument for measuring a static electric field would be based partly on a conventional rotating-split-cylinder or rotating-split-sphere electric-field mill. However, the design of the proposed instrument would overcome the difficulty, encountered in conventional rotational field mills, of transferring measurement signals and power via either electrical or fiber-optic rotary couplings that must be aligned and installed in conjunction with rotary bearings. Instead of being made to rotate in one direction at a steady speed as in a conventional rotational field mill, a split-cylinder or split-sphere electrode assembly in the proposed instrument would be set into rotational vibration like that of a metronome. The rotational vibration, synchronized with appropriate rapid electronic switching of electrical connections between electric-current-measuring circuitry and the split-cylinder or split-sphere electrodes, would result in an electrical measurement effect equivalent to that of a conventional rotational field mill. A version of the proposed instrument is described

Distribution automation applications of fiber optics

Motivations for interest and research in distribution automation are discussed. The communication requirements of distribution automation are examined and shown to exceed the capabilities of power line carrier, radio, and telephone systems. A fiber optic based communication system is described that is co-located with the distribution system and that could satisfy the data rate and reliability requirements. A cost comparison shows that it could be constructed at a cost that is similar to that of a power line carrier system. The requirements for fiber optic sensors for distribution automation are discussed. The design of a data link suitable for optically-powered electronic sensing is presented. Empirical results are given. A modeling technique that was used to understand the reflections of guided light from a variety of surfaces is described. An optical position-indicator design is discussed. Systems aspects of distribution automation are discussed, in particular, the lack of interface, communications, and data standards. The economics of distribution automation are examined

High speed polling protocol for multiple node network with sequential flooding of a polling message and a poll-answering message

The invention is a multiple interconnected network of intelligent message-repeating remote nodes which employs a remote node polling process performed by a master node by transmitting a polling message generically addressed to all remote nodes associated with the master node. Each remote node responds upon receipt of the generically addressed polling message by sequentially flooding the network with a poll-answering informational message and with the polling message

Phase-locked loop FM demodulator

A conventional phase-locked loop is improved by replacing its phase detector with one comprising a linear ramp generator and a sample-and-hold circuit, thus eliminating the need for a lowpass loop filter, although the output of the sample-and-hold circuit may be filtered in the case of a very low level modulating signal on the incoming FM signal, but then filtering is not a difficult problem as in a conventional phase-locked loop. The result is FM demodulation by zero-order estimation. For FM demodulation by first-order estimation, the arithmetic difference between adjacent samples is formed, and using a second sample-and-hold circuit an arithmetic difference signal is produced as an input to a second ramp generator that is reset after each sampling cycle to generate a ramp the slope of which is a function of the arithmetic difference signal stored in the second sample-and-hold circuit. The ramp thus generated by the second ramp generator is arithmetically summed with the zero-estimation signal from the first sample-and-hold circuit to form a first-order estimation signal. Filtering such a first-order estimation signal is less of a problem than filtering a zero-order estimation signal

Communications and control for electric power systems: Power system stability applications of artificial neural networks

This report investigates the application of artificial neural networks to the problem of power system stability. The field of artificial intelligence, expert systems, and neural networks is reviewed. Power system operation is discussed with emphasis on stability considerations. Real-time system control has only recently been considered as applicable to stability, using conventional control methods. The report considers the use of artificial neural networks to improve the stability of the power system. The networks are considered as adjuncts and as replacements for existing controllers. The optimal kind of network to use as an adjunct to a generator exciter is discussed

The case for redefinition of frequency and ROCOF to account for AC power system phase steps

All conventional techniques for measuring frequency result in large deviations to the perceived or calculated frequency when the AC waveform undergoes a phase step. The deviation magnitude and duration are dependent on the phase step magnitude, and the applied windowing/filtering. Such phase steps do occur in the power system, and the erroneous frequency calculation can result in inappropriate reactions by some rapidly-responding control and protection systems. If the frequency measurand is further differentiated to ROCOF (Rate of Change of Frequency), the excursion magnitudes can become far larger than any normally expected values of ROCOF. This paper discusses the meaning of the terms frequency and ROCOF, and presents a modified concept of frequency and ROCOF. This is done by allowing rapid phase steps to be disaggregated from frequency in the AC waveform model equation. This allows new measurands “underlying frequency”, and “underlying ROCOF” to be defined, as a pair of linked parameters, independent from a separate dynamic phase parameter. These new measurands have the potential to offer much more useful and stable information to be sent to fast-acting control and protection systems, than the existing measurands of AC frequency and ROCOF, particularly during fault events and large switching or disconnection events

Smart grid measurement uncertainty : definitional and influence quantity considerations

Measurement uncertainty, in general terms, is an expression of the quality of a measurement. It is typically quan- tified by defining the location and spread of the distribution of a hypothetical infinitely large number of measurements of the thing being measured. The Guide to the Expression of Uncertainty in Measurement (GUM) classifies uncertainties according to whether they are evaluated by statistical means or not. The GUM also mentions that an incomplete definition of the measurand can give rise to large uncertainty in the result. For some of the quantities measured in the Smart Grid, it may be that this "definitional uncertainty" could be a major source of problems. Influence quantities may have a bearing on the result of a measurement without being the subject of the measurement. For example, signal harmonics, noise and temperature effects, while not desired as part of a measurement, exist in power system signals being measured, and they have (sometimes significant) effects on the measurement process

Sociophonetic variation in a long-term language contact situation: /l/-darkening in Welsh-English bilingual speech

This study investigates /l/-darkening in the Welsh and English speech of bilinguals in North Wales. Although it is claimed that /l/ is dark in all syllable positions in northern varieties of both languages, there have been no quantitative investigations of this feature which consider cross-linguistic phonetic differences, the differing nature of language contact between North East and North West Wales, and differences in the way both languages are acquired by speakers. The dataset of 32 Welsh-English bilinguals, aged 16-18, was stratified by speaker sex, home language, and area. Tokens of /l/ in word-initial onset and word-final coda positions were analysed acoustically. The results show cross-linguistic differences in onset position and that such differences were found to be greater in the speech of female participants and those from North West Wales. Differences were also found between Welsh-dominant and English-dominant communities. These results are discussed with reference to the influence of extra-linguistic factors on speech production and the possible social meaning associated with dark /l/