By Phil Kreveld
The nightmare of monitoring 500,000-plus low-voltage transformers as envisaged in the 2026 Integrated System Plan of the Australian Energy Market Operator (AEMO) urgently requires a wakeup call. Why even contemplate such a Herculean task? It is a pedestrian approach to solving the clash between millions of the nation’s rooftop solar systems turning ‘their backs’ on ‘far away’ costly energy via buildout of high-voltage transmission and large-scale wind and solar generation. Those rooftop solar systems are going for energy independence. So, AEMO is figuring on having to subdue ‘mum and dad’ generation in favour of the ‘big end of town’. AEMO denies it officially but measures such as Emergency Backstop—shutting down household inverters when grid stability is threatened—prove otherwise. Take transmission owner Transgrid’s expectation that electricity demand will hit zero in spring afternoons next decade and therefore will require costly investment (Australian Financial Review, August 19).
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Rather than cutting the Gordian Knot and freeing distribution networks from the shackles imposed by diktats of energy tsars, we are speeding headlong to the clash of technologies; one ancient, of distant power stations and long transmission lines, and the other, the democratisation of electrical energy. Democracy is messy—the millions of solar inverters with only some being completely compliant to AS/NZS 4777 and the latest restrictions imposed by Emergency Backstop, are an unruly lot. Hence, AEMO’s messy idea is to somehow ‘colander’ grid operating instructions out of half a million transformer monitoring measurements. Rather than waking to this reality, we are shoehorning the evermore energy-independent distribution networks into an electricity system whose cobwebbed philosophies harken back to the early days of electricity, now two centuries old!
The impossible dream can become a reality by contemplating a new reality, i.e., the advantages of increasingly energy-independent distribution networks. And we are the stand-out in Australia—no one in the world has our level of domestic solar penetration! In short, breaking the constraining ties of synchronicity simultaneously achieves energy independence and security of electricity supply. Right now, the alternating current electricity system, from the furthest generator to the last house in the street, beats at the same heartbeat. AEMO is the anxious cardiologist constantly checking for any sign of arrhythmia (frequency) and blood pressure (voltage). This task, growing more onerous with the construction of longer and longer transmission lines, can be relieved by judiciously swapping alternating (AC) current with direct current (DC) in distribution networks—and setting them free from heartbeat synchronicity. This is achievable through the replacement of traditional transformers with smart transformers, the latter providing direct current (DC) energy storage, as well fulfilling the essential task of reducing voltage to the low level for households and businesses. The transformation taking place in smart transformers is to convert AC to DC at higher voltage, transforming higher DC voltage to lower DC voltage, and then converting to lower AC voltage suitable for consumers of electricity.
The foregoing might appear convoluted, however, it breaks the constraining nexus of synchronicity with transmission—and realises the dream—the conversion of distribution networks to mosaics of interconnected microgrids. This is made possible because the intermediate AC to DC, and subsequent DC to AC steps, provide battery storage opportunities at both the primary (higher voltage) and secondary (low voltage) side. This already solves a major headache of reverse power flow during days of high solar production and minimal energy usage. The wonderful advantages of turning distribution networks into federations of microgrids, are twofold: (1) increased security of supply and—in the case of some massive outage, restarting supply at local level, and (2) putting a break on the buildout of more and more transmission lines, as well as injudiciously selected remote energy zones.
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The engineering behind smart transformers is well established; it is already there in lots of power electronics for the electrical power industry including all manner of compensation devices and inverters (DC to AC) and converters (AC to DC). European countries, many without the sunshine we enjoy, are trialling smart transformers, and in our neighbourhood, in Singapore. We here are held back by the energy tsars, i.e., the regulatory authorities, and the truly impossible dream of politics: zero emission, zero disruption to investment strategies; and zero increases in energy charges. The latter can be minimised but not by rhetoric—only by imagination followed by a concentrated and imaginative engineering effort. We are already world leaders in rooftop solar energy. Nothing stops us from being leaders in realising its enormous potential by bringing energy creation and its consumption back home.
