precipitated As the current in the inner city of Zurich on Wednesday evening, some will think: again! A sense of Déjà-vu had especially to commuters in Central station, where it was first grown in the middle of December already, once suddenly dark. Zurich is the city of light deletion? Current Figures of the power plant EWZ show: The power supply has become in the last few years, actually a little unreliable, but at a high level. In comparison with other municipalities of Zurich is still good.

for the perception of a significant difference to a village in the country is: When it comes to short-circuit that makes the rule, not the headlines. On the other hand, in the middle of the city to a large-scale Blackout, know it immediately, tens of thousands – and it becomes the topic in the media. Especially if it happens during rush hour to the train station as yesterday. The keywords “power outage Zurich” module in Google Switzerland immediately of the most searched terms. This effect was already evident in the sensational power outages in 2015, 2016 and 2017.

nine and a half minutes – as long as the average EWZ-customer was last a year without electricity.

The excitement is in contrast to a value other: nine and a half minutes – as long as the average EWZ-customer was last a year without electricity. Being average does not mean, of course: Some sat in darkness any longer, other. This so-called Saidi value is used internationally to measure the reliability of electricity networks. In the cities of Winterthur and Uster he was in the last few years under nine minutes, which is slightly better than in Zurich; about the whole of Switzerland considered, the Saidi value, however, in the case of eleven and a half minutes and is higher.

Of the 137 power outages that took place in Zurich last year, most were only minor events. Sometimes only affected a single property. In addition, long fractures in the city are less likely than elsewhere. This is because the grid of the EWZ has a redundant structure: first, it has several leads, secondly, are distributed 14 sub-stations over the city, the current can rapidly be on a different distribution node are redirected, if one fails. If, however, in a country parish in the single supply line fails, it may take a Blackout for hours. So, for example, in Stäfa, than a year ago due to storm Burglind trees on a high-voltage line dumped.

However, the reliability of the city’s network has slowed in the last decade measurable. The Saidi value is increased from five and a half minutes to almost ten. Once he was even about, what the EWZ missed its own target of just below.

When electricity supplier to back this unpleasant development to the brisk construction activity in the city. By 2015, about half of the interruptions went to the account of construction companies, who separated, for example, when digging a line.

The EWZ increased since then, its information campaigns and announced at the same time, more consistent against the ‘polluter pays’ approach. After it is moved, in one case, the construction worker, successfully, in court, has spoken of this in the industry. The shows seem to have an effect: The share of the so-caused Power interruptions. Today, he is 40 percent, what is, according to the EWZ-media speaker Harry Graf is still a lot.

However, The headline-grabbing, nationwide power outages of the past few years, the fall is also statistically significant, were rarely the result of construction work. The reasons were on the one hand, squirrels, dormice and bramble Bush, which provided a lot of discussion. On the other hand, there were technical Defects. The second most common reason for power outages in the city banal: material fatigue is more likely. (Tages-Anzeiger)

Created: 28.03.2019, 16:15 Uhr