Smart grids better able to withstand climate change challenges

The risk of serious storms and hurricanes in the Gulf of Mexico and along the Atlantic coast is also rising. In October 2015 Hurricane Patricia, one of the most powerful storms on record, slammed into Mexico’s southwestern coastline packing wind speeds of up to 400 kph. Many buildings, transformers, and overhead lines in the path of the storm were severely damaged by associated flooding. In early October, Hurricane Joaquin threatened the Atlantic coast with wind speeds of up to 250 kph (150 mph and more). Though the storm just bypassed the mainland, its offshoots and a low pressure area over the mainland caused the worst rains since records began in South Carolina — no small reason why the Department of Energy is warning about the urgent need to arm the power grid against extreme weather.

Two control centers
PJM Interconnection is well aware of the growing threats posed by climate change. Since November 2011 it has had an energy management system from Siemens that makes it possible to take stock of a grid during outages and manage it better. Siemens says that the system uses two control centers that manage the grid jointly during normal operation. If one is knocked out in an emergency, the other can handle operations by itself. This was exactly what happened when Hurricane Sandy crossed the region. PJM never lost its view of the status of its transmission grid.

The grid management system is based on an integrated platform developed by Siemens and PJM Interconnection, a platform which is able to combine a variety of applications such as energy, market, and distribution network management systems together. “The system’s open architecture is its strength. At low expense, it integrates not just new applications but old ones as well,” says Ravi Pradhan, Vice President of Technology Strategy at the Siemens Energy Management Division in Minneapolis.

“That way, solutions that are already available can be included, while operating two control rooms at the same time increases the grid’s safety, especially in grid-wide emergency situations like a hurricane.”

Intelligent robustness the order of the day
But it is not just the interregional power grid that needs to be more robust — so does the local grid in New York City. After the destruction from Hurricane Sandy — more than a million New Yorkers were left without power for days — power utility Con Edison has been implementing a billion-dollar-plus plan since 2013 to enhance the resilience of the city’s grid against extreme weather events by 2017. For example, it is protecting power plants, substations, and switchgear with higher dams, protective walls, and reinforced doors. Robust power poles are being raised, monitoring sensors will be installed in the grid, and overhead lines for critical facilities such as police and fire departments, hospitals, pharmacies, and supermarkets will be re-laid underground.

Siemens notes that in the summer of 2015, it helped Con Edison start up a new automation system for two distributor networks in Manhattan. The networks can be split up into a total of four sub-networks in a fraction of a second if they are in a danger of being flooded. If a disruption occurs — for example, if a substation explodes, as happened during Sandy at the eastern end of 14th Street in Manhattan — the incident is isolated. It cannot ripple through the rest of the network.

This cutoff is handled by way of a number of centrally controlled switching stations. Con Edison’s two distribution networks in Lower Manhattan have forty-four such stations installed underground. Once the control room triggers the separation, as many as twenty switches are simultaneously activated within milliseconds. The challenge is to actuate such a large number of switches, distributed all over the network, almost simultaneously. To meet this goal, the system relies on a redundantly designed, fiber-optic network.

Siemens says that before this automated switching system entered service, the company tested the entire solution to ensure that it could handle the required simultaneous switching speeds. It was a success. “This is the first time synchronous switching has been established in a distribution system,” says Andre Smit, Chief Engineer for the Siemens Energy Management Division in Wendell, North Carolina. When the next storm comes along, he says, the southeast corner of Manhattan — which includes Wall Street — can be isolated if necessary from the rest of the city as fast as lightning.