Architecture of a network-in-the-Loop environment for characterizing AC power system behavior

This paper describes the method by which a large hardware-in-the-loop environment has been realized for three-phase ac power systems. The environment allows an entire laboratory power-network topology (generators, loads, controls, protection devices, and switches) to be placed in the loop of a large power-network simulation. The system is realized by using a realtime power-network simulator, which interacts with the hardware via the indirect control of a large synchronous generator and by measuring currents flowing from its terminals. These measured currents are injected into the simulation via current sources to close the loop. This paper describes the system architecture and, most importantly, the calibration methodologies which have been developed to overcome measurement and loop latencies. In particular, a new "phase advance" calibration removes the requirement to add unwanted components into the simulated network to compensate for loop delay. The results of early commissioning experiments are demonstrated. The present system performance limits under transient conditions (approximately 0.25 Hz/s and 30 V/s to contain peak phase-and voltage-tracking errors within 5. and 1%) are defined mainly by the controllability of the synchronous generator

“No Country for Old Men”: a Note on the trans-Tasman Income Divide

Although much work has been done analysing the possible causes of the New Zealand-Australian income gap, to date there has been little analysis of the extent to which this gap differs by gender and age. Using New Zealand and Australian employment and census data we examine these differences and find that (1) over the last 25 years the incomes of New Zealand women have declined less rapidly than those of New Zealand men, relative to Australian incomes; (2) this poor relative performance of New Zealand males was felt most by those in middle age; and (3) the stronger relative income growth of New Zealand females appears to be largely driven by increased public sector wage growth, and as such, its long term sustainability is questionable.dynamic optimisation, electricity spot market performance, stochastic fuel availability, storage options, climate change

Frequency and fundamental signal measurement algorithms for distributed control and protection applications

Increasing penetration of distributed generation within electricity networks leads to the requirement for cheap, integrated, protection and control systems. To minimise cost, algorithms for the measurement of AC voltage and current waveforms can be implemented on a single microcontroller, which also carries out other protection and control tasks, including communication and data logging. This limits the frame rate of the major algorithms, although analogue to digital converters (ADCs) can be oversampled using peripheral control processors on suitable microcontrollers. Measurement algorithms also have to be tolerant of poor power quality, which may arise within grid-connected or islanded (e.g. emergency, battlefield or marine) power system scenarios. This study presents a 'Clarke-FLL hybrid' architecture, which combines a three-phase Clarke transformation measurement with a frequency-locked loop (FLL). This hybrid contains suitable algorithms for the measurement of frequency, amplitude and phase within dynamic three-phase AC power systems. The Clarke-FLL hybrid is shown to be robust and accurate, with harmonic content up to and above 28% total harmonic distortion (THD), and with the major algorithms executing at only 500 samples per second. This is achieved by careful optimisation and cascaded use of exact-time averaging techniques, which prove to be useful at all stages of the measurements: from DC bias removal through low-sample-rate Fourier analysis to sub-harmonic ripple removal. Platform-independent algorithms for three-phase nodal power flow analysis are benchmarked on three processors, including the Infineon TC1796 microcontroller, on which only 10% of the 2000 mus frame time is required, leaving the remainder free for other algorithms

MIGRATIONS, Film Festival, New Orleans, USA

The Front's 3rd annual open call film festival highlights themes of migration. Presenting a series of short films that address individual journeys, concepts of home, radically shifted perspectives, belonging, and place within the larger context of mass groups of people escaping their homeland for safer ground, being forced out of their own territories, and banned from others

MIGRATIONS, Film Festival, New Orleans, USA

The Front's 3rd annual open call film festival highlights themes of migration. Presenting a series of short films that address individual journeys, concepts of home, radically shifted perspectives, belonging, and place within the larger context of mass groups of people escaping their homeland for safer ground, being forced out of their own territories, and banned from others

Voting at 16 – lessons for the future from the Scottish Referendum

The 2014 Referendum on Scottish independence raised many issues about the future of Scotland. It also produced an innovation as regards the electoral process by making 16 years the minimum age of participation. This article examines issues surrounding the voting age and draws on a schools-based study, which shed light on teacher and pupil opinion about this lower than usual threshold for voting. It is also concerned with how schools cover the teaching of politics and prepared students for the Referendum debate within a context of expected neutrality on a highly divisive matter. Some implications of extending the lower voting age for future elections are discussed

Influences of Egyptian Lotus Symbolism and Ritualistic Practices on Sacral Tree Worship in the Fertile Crescent from 1500 BCE to 200 CE

Many conventional features of world tree motifs in the ancient Near East—including stalked palmettes, aureoles of water lily palmettes connected by pliant stems, floral rosettes, winged disks and bud-and-blossom motifs—trace largely from Egyptian practices in lotus symbolism around 2500 BCE, more than a millennium before they appear, migrate and dominate plant symbolism across the Fertile Crescent from 1500 BCE to 200 CE. Several of these motifs were associated singularly or collectively with the Egyptian sema-taui and ankh signs to symbolize the eternal recurrence and everlasting lives of Nilotic lotus deities and deceased pharaohs. The widespread use of lotus imagery in iconographic records on both sides of the Red Sea indicates strong currents of cultural diffusion between Nilotic and Mesopotamian civilizations, as does the use of lotus flowers in religious rituals and the practice of kingship, evidence for which is supported by iconographic, cuneiform and biblical records. This perspective provides new insights into sacral tree symbolism and its role in mythic legacies of Egypt and the Middle East before and during the advent of Christianity. Closer scholarly scrutiny is still needed to fully comprehend the underlying meaning of immortalizing plants in the mythic traditions of Egypt, the Levant and Mesopotamia

Graphite core brick crack detection through automated load trace analysis

This presentation looks at graphite core brick crack detection through automated load trace analysi

"No country for old men": A note of the Trans-Tasman Income Divide

Although much work has been done analysing the possible causes of the New Zealand- Australian income gap, to date there has been little analysis of the extent to which this gap differs by gender and age. Using New Zealand and Australian employment and census data we examine these differences and find that (1) over the last 25 years the incomes of New Zealand women have declined less rapidly than those of New Zealand men, relative to Australian incomes; (2) this poor relative performance of New Zealand males was felt most by those in middle age; and (3) the stronger relative income growth of New Zealand females appears to be largely driven by increased public sector wage growth, and as such, its long term sustainability is questionable