Leaking, Arcing Transformer Needs Xcel's Attention

IRONWOOD, MI - Monday, July 14, 2008 - Repeated complaints to Xcel Energy regarding a leaking, arcing transformer on the corner of Michigan Avenue and Hemlock Street have gone unanswered.

Transformers make transmission of electrical energy over long distances possible. High voltage travels over wires with less resistance (reduced current) than lower voltage. Step-Up transformers increase the voltage, making it economically feasible to transmit the energy over long distances. Before the electrical energy can be used by the consumer, the high-voltage needs to be reduced. Step-Down transformers, like the one pictured in this article, are used to reduce the voltage.

Transforming high-voltage to a useable form creates heat. Step-Down transformers are filled with oil that serves two purposes. The oil acts as a coolant and also an insulator of the electrical current.

Polychlorinated biphenyls (PCB rich oils) were commonly used as a coolant/insulator in older transformers. Concerns over the toxicity and environmental persistence of PCB's led to a widespread ban on their use.

Today, non-toxic, stable silicone-based oils, or fluorinated hydrocarbons are used to cool and insulate transformers. Before 1977, even transformers that were normally filled only with mineral oils commonly also contained polychlorinated biphenyls as contaminants at 10-20 ppm. Since mineral oil and PCB fluid mix, maintenance equipment used for for both PCB and oil-filled transformers could carry over small amounts of PCB, contaminating oil-filled transformers.

According to a neighbor who lives near the transformer, "I reported this transformer at first because it arcs continuously (bright light at night) and makes reception of AM broadcast stations from anywhere other than Ironwood impossible."

The neighbor says the transformer is clearly leaking the PCB rich oil onto the property of a home owner near the service pole.

"I first contacted Xcel about this at the end of April." the complaintant stated, "On May 5th they met with me and we looked at the transformer. They promised to replace it within 3 to 4 weeks. Calls to them after this had elapsed, resulted in statements like 'we're awful busy' and 'we don't know when we can get to it.'"

"They are clearly not going to replace this transformer until it is low enough on the PCB rich oil that it explodes."

The reason transformers arc continuously is due to a lack of oil. When the oil levels drop, the formerly submerged windings inside the tranformer are no longer insulated. The uninsulated windings overheat and eventually will fail, often resulting in a violent combustion.