MASSENA - Massena Electric Department officials are sending a transformer from their East Hatfield substation for repairs and are crossing their fingers that they will not have to purchase a new one.
Some abnormal oil readings were observed in a transformer last month, leading to additional testing by the Cicero-based engineering group HMT.
“(In) the beginning of May, we had some unacceptable oil readings with high acetylene. We did a retest to confirm the reading and then we did Doble testing,” MED Superintendent Andrew J. McMahon said during June’s board meeting, referring to a power factor test performed on transformers to ensure they are functioning correctly.
“As a result, during the Doble testing — the electrical testing that was going on — we seem to have uncovered where the hot spot had come from. It was a hot spot that led to the bad oil readings. We think we found where that is.”
Based on consultations with HMT, the consensus was to re-energize the transformer, which was done last month.
Further testing was conducted this week and more potential issues were noticed.
“(HMT), they were in today and they’ve been Doble testing and the Doble testing is the test that would indicate the health of the core - the copper winding which is the high value part of the equipment. That all indicates that it’s fine and the oil testing that we’ve done indicates that the paper is fine. There’s paper insulation between the copper winding. So that’s all good,” Mr. McMahon said. “The problem is... the oil testing indicated that there was a hot spot. ... The oil tests indicated that there’s something burning in there because we have high ethane, high ethylene, and then we had high acetylene.”
Mr. McMahon said the likelihood is that somewhere on the transformer where there is supposed to be a connection there is a loose area.
“Through the course of doing the Doble testing, they’ve narrowed it down where we think it’s the Delta-Wye switch that there’s something not making good contact there or the resistance level is high. We thought we resolved it about a month or six weeks ago when they were in and they did the first Doble test and they thought they had cleaned it off and everything seemed to operate fine,” he said. “Everything was going fine and the gas and oil readings were all trending down, which would you would expect to happen as you load it up.”
As MED officials began to put more load on the tranformer during a four-day stretch that ended Monday, acetylene levels began to skyrocket.
“Two months ago, (the acetylene) was at 63. A high reading for acetylene is like 30 or 35, so when it hit 63 that’s when we panicked. But once we resolved it, the acetylene started to burn off so the acetylene went from 63 to 40 and down to 35,” Mr. McMahon said. “Then last Friday when we put the extra load on it, it jumped from 33 to 38. So it had our attention and we said, ‘Let’s find out now.’ (We) added more load to it and it went from 38 to 133.”
The superintendent said that there are three separate paths for the department to take now.
The goal, Mr. McMahon said, is to have a new or repaired transformer in place for the next winter season.
“We’re going to take this transformer out as soon as possible and ship it to a shop in Pennsylvania. They’ll take off the (transformer) cover and be able to see. If there’s a hot spot in there, it’s going to be plain as day and hopefully there is something evident one way or another,” he said.
“If it’s a straight forward fix, I think we should do it. If it’s a winding (issue), without knowing the particulars, you’re going to spend probably $80,000 for a rewind and probably $160,000 for a new one.”
MED officials said the transformer being sent for further evaluation was installed in 1995. The units are capable of lasting approximately 50 years, according to Mr. McMahon.