Con Edison, a power company that serves ten million customers in New York City and nearby Westchester County, has also taken preventive measures since Hurricane Sandy. From 2013 to 2017, the company implemented a billion-dollar plan that protects its entire power grid against extreme weather conditions. Among other things, Con Edison is reinforcing doors and increasing the height of dikes and protective walls in order to protect power plants, transformer substations, switchgear, and other systems. In addition, the company is erecting robust transmission towers, installing surveillance sensors throughout its grid, and replacing overhead power lines for key facilities such as police stations, fire departments, hospitals, pharmacies, and supermarkets with underground facilities.
In the summer of 2015, Siemens helped Con Edison to put new automation technology into operation for two distribution systems in lower Manhattan. If a flood appears imminent, the new technology can split the distribution systems into four sub-grids in a fraction of a second. As a result, disruptions such as the explosion of a transformer substation at the eastern end of East 14th Street during Hurricane Sandy can no longer spread to the rest of the grid.
The sub-grids are separated by a number of centrally controlled switching stations. The two distribution systems have 44 of these switching stations, which have been installed underground. If the separation of the sub-grids is manually triggered at the control center, up to 20 switches have to be simultaneously activated within a few milliseconds. It’s quite a challenge to simultaneously activate such a large number of switches spread across the entire grid. As a result, such commands are now transmitted through a fast and redundant fiber-optic network.
Before installing its controllers, Siemens tested the entire solution to make sure that it can simultaneously activate the switches at the required speeds. The test was successful. “This was the first time that synchronous switching was achieved in a distribution system and the first time that the IEC 61850 Goose standard was used for synchronous switching underground,” says Chief Engineer Andre Smit from Siemens Digital Grid Energy Management Systems in Wendell, North Carolina. When the next storm arrives, the system could, if necessary, instantly isolate the southeastern corner of Manhattan (which includes Wall Street and thus the financial center of the United States) from the rest of New York.