New York’s first mobile emergency transformer

Just 36 hours from installation to switch-on - New York energy supplier Con Edison's first mobile emergency transformer went online in record time. PFISTERER was involved from the outset in planning this new type of transformer, and supplied the dry pluggable CONNEX connection technology that forms a key element of the integrated solution.

The risk of blackouts due to faulty power transformers is increasing worldwide, triggered not only by the advancing age of many units, but also due to extreme natural phenomena such as storms, floods and lightning. For this reason, Con Edison wanted a forward-looking capability to react quickly in a real emergency - a power failure would hit many of New York's nine million inhabitants. The long-established energy company has been supplying the city with electricity for over 180 years.


Smart idea: extension cables for substations

Typical substations are rarely so spacious that they can easily accommodate additional transformers. So it’s usually difficult to position the mobile units close enough to the faulty transformer’s connection points. But here too, PFISTERER’s pluggable connection system offers a solution. CONNEX-equipped transformers can be connected via 60-metre MV and HV cables, which means they can be sited at a substantial distance. “One transformer in New York was actually more than 100 metres away. But thanks to our pluggable cast resin joint, we can easily join two or more cables together, like an extension cord. Which means bridging sizeable distances is no problem,” reports Peter Müller, project manager at PFISTERER.

The premiere for the emergency transformer system was a total success, and its use is not restricted only to emergencies. Thanks to a variety of connections for 345 kV, 138 kV and 69 kV, the emergency transformer can replace any existing transformer in Con Edison’s supply area, which means there is no need to keep a separate reserve unit for each voltage rating. That significantly reduces total investment as well as storage expenses. The energy supplier already owns a second mobile system for regular maintenance work

Fast installation - thanks to CONNEX

The solution is based on easily transportable single-phase emergency transformers, which are combined at the deployment location into a three-phase transformer. The connection concept was developed by PFISTERER. Thanks to the pluggable, touch-safe CONNEX system, installing a mobile emergency transformer is up to 75% faster. Time-consuming oil work is completely eliminated, since the transformers are hermetically sealed and factory pre-tested together with their bushings. The trial run at Con Edison shows that the power supply can be restored in a few days following a blackout. It took the team just 30 hours to put the transformer into service, and the voltage was ramped up to full power on the same day.