PPL launches circuit breaker replacement project

As part of a system-wide modernization program, PPL Electric Utilities intends to invest $91 million over the next five years to replace breakers at 69 kV, 138 kV, 230 kV and 500 kV substations. The company is currently reviewing additional steps it may take from 2016-2020.

Based in Allentown, Pa., PPL Electric Utilities serves 1.4 million electric customers in 29 counties of eastern and central Pennsylvania. Its service area spans 10,000 square miles. PPL operates and maintains nearly 400 transmission and distribution substations on its system.

The substation upgrades are part of a larger asset optimization strategy that covers $2 billion in new and improved transmission and distribution infrastructure investments over the next 10 years. The program outlines the steps the company must take to proactively replace deteriorating equipment. It also helps ensure ongoing, reliable electric system performance, as well as enhanced maintenance practices to preserve a T&D asset's availability and reliability.

The project reduces PPL Electric Utilities' carbon footprint because the replacement breakers, primarily the 230 kV variety, contain much less sulfur hexafluoride gas than their aged predecessors. The gas, more commonly known by its SF6 designation, has a global warming potential 23,900 times greater than carbon dioxide, according to the federal government.

Pressurized SF6 acts to open and close switch contacts and interrupt electric current in the breakers. It has the potential to get into the atmosphere through leaks around equipment seals or through inspection or maintenance covers.

Of the work planned this year, 27 of the 30 230 kV breakers currently use SF6. Two new 230 kV breakers went into service recently at the Brunner Island power plant and one at the Montour plant, both located in Pennsylvania. Work to replace others already is in progress.

Replacement of 230 kV and 138 kV breakers are being purchased from Mitsubishi Electric Power Products Inc., while 500 kV breakers will come from ABB and 69 kV breakers from Siemens. Matrix Service Industrial Contractors Inc. performed the substation work in coordination with PPL project engineers.