By Phil Kreveld, Power Parameters
The All Energy Conference (Melbourne, October 23 and 24) in its scope of energy strategy, energy trading and technical matters that were the subject of presentations and discussions, though of value, demonstrated the confusing intersection of regulatory, business and grid-operational requirements in the electricity sector. A chief conception to emerge from many presentations is that the electricity ‘poles and wires’ are somehow much like communication links with ‘open standards’. In other words: sending electrical power hither and yon is much like the internet. Electrical engineers felt under pressure to defend their patch, and had some justification for the apparent trivialising of electrical stability that emerged from some presentations.
The network stability topic received adequate attention in the many technical presentations with particular focus on voltage regulation such as proposed solutions for reactive power support in network fringes and IoT schemes to balance battery storage opportunities against domestic load requirements and voltage rise at distribution transformers. There was evidence of frustration of solar PV engineering companies with network providers restricting access of large, typically in excess of 100 kilowatts, installations. One technical exposure of problems in connecting to networks highlighted requirements that seemed to have little bearing on stability but may well have been imposed as a congestion-avoiding measure in the interests of other connected consumers.
Discussion of the problems encountered in remote renewable energy zones underscored the considerable challenges in connection solar and wind farms to transmission lines and the need for augmentation of transmission lines with low reactive impedance to resistance ratios. Solutions mentioned were synchronous condensers, static var compensators and ‘virtual first swing’ inertia mimicking for inverters. Virtual inertia is underexplored at present but is an important way of improving frequency stability. Marginal loss factors are a negative feature of remote node points and reducing voltage to power ratio sensitivity for remote area lines is necessary.
Emerging from the conference is how unlike the rest of the developed world Australia’s electricity sector is because of the uncontrolled way domestic solar PV has grown and is continuing to grow thus creating a headache for network providers. There were a number of presentations covering fringe of network conditions under high solar PV penetration. The absence of control over solar inverters creating problems for networks as well owners of installations received much attention. Discussion centred on state discovery in order to uncover congestion bottlenecks in fringe networks and on the need for inverter control. As to state discovery, the extensive installation of smart meters in Victoria is allowing network providers to model voltage regulation correlation with Bureau of Meteorology data accurately. In Queensland, utilising relatively few monitoring points, work on state discovery was undertaken and resulted in a high level of predictability of voltage regulation.
A salient feature of this latest of many electricity sector conferences is the difficulty of harnessing the many very good technological developments that are being created in academia and in some network companies, who are certainly investing in highly skilled engineers and scientists, but fail to put new technologies to the practical test. For example, an excellent simulation study on network voltage regulation is not being taken further by implementing control schemes to limit voltage fluctuation for consumers so as to provide them with less energy consumption and more energy export potential. The reason although not mentioned by the presenters is not difficult to find as the investment climate is very negatively affected by the lack of clear market signals.
Australia experiences a high degree of politicisation of electricity prices, undoubtedly high although not as is sometimes claimed, the highest in the world, and in the green energy ‘debate’. The latter is not so much a debate as that term implies discussions of possible solutions based on agreed data; rather, it is more like barrage of opinions based on fixed positions. The conference makes plain to this observer that an overarching engineering plan encompassing synchronous generation, transmission and distribution is very much needed if we are to transition towards a high renewable energy target. However, somewhat like the newcomer to Ireland, who on asking a local on how to get to Kilkenny, was told: “well, if I were you, I wouldn’t be starting from here”, we have a similar situation. The plethora of authorities and private commercial interests make such an overarching engineering template nigh on impossible.