Utilities are experiencing problems that are not easily detected anymore because of a reduction of personnel and older maintenance practices. They need clear-cut methods for improving breaker performance while allowing them to reallocate resources to the substation equipment that has the greater need.

The “Analyzing First-Trip Test Results” session at the Finepoint Circuit Breaker Test and Maintenance Training Conference will provide some solutions to problems that need to be addressed. The session, which will be held on Wednesday, Oct. 8, will feature Joseph Peters, senior supervising engineer in the field engineering group at NSTAR Electric in Boston, and Randy Cox, sales and support manager for Kelman, North America.

“Utilities have experienced a reduction in both manpower and O&M funding, creating the need to have the right tools to locate potential problems, as opposed to a rigid, cost-prohibitive, time-driven maintenance programs,” Cox said. “In other words, why spend time and money on something that doesn’t need attention?”

The session is a brief introduction to the value of capturing the first trip on any circuit breaker while the breaker is either being removed from service or tied to another breaker, and comparing that data to an immediate second trip. The presenters will discuss why this is important and necessary to finding the issues that lay hidden within each circuit breaker.

As part of the discussion, Peters and Cox will discuss the importance of measuring and evaluating the operating coil’s current signature. When called upon to operate, the circuit breaker’s operating coils will produce a specific current profile, which can then be evaluated in detail with the appropriate software. When the breaker’s operator is functioning as designed, the current profile of the breaker’s operating coils will be repeatable. As problems develop with the operator, these current profiles will change, alerting the user to a developing problem.

NSTAR has worked with Kelman to find a more efficient way to identify circuit breaker problems. Peters of NSTAR will be presenting several case studies that his company has performed using Kelman’s Profile P2 breaker operator analyzer. The case studies will include breakers the utility has personally found to be on their way to problems. The section will discuss how the program was implemented, what was found, how the company prioritized the work, and the overall success of the program.

“Our 4-kV system is old and expensive to upgrade,” Peters said. “We had experienced bus section outages causing a large number of customer outages as a result of a street fault. The feeder breaker did not trip, but the upstream transformer secondary and or bus tie tripped. After the fact, testing revealed no problem.”

Peters said that NSTAR is now obtaining breaker first-time trip timing of its 4-kV distribution systems. NSTAR will soon test its 14-kV system and will use the P2 analyzer on 115-kV breakers as well.

Peters further explained NSTAR’s experience: “We suspected a slow breaker, but when tested on the test stand, and after being cycled a few times, timing was within specifications,” he said. “We suspected and later proved that the breaker was in service for several years without being operated, the grease had hardened--which caused a delay in opening on first trip. We can also evaluate the DC battery and charger system during a trip. Breaker first-trip timing has been incorporated in a full, functional switchgear testing of bus swap-over and reclosing schemes.”

Joseph Peters is a senior supervising engineer in the Field Engineering Group of NSTAR Electric, located in Boston, Massachusetts. His current duties include supervision of power system engineers and technicians. He has worked for NSTAR (Boston Edison) for more than 27 years. His overall work history includes: electrician, foreman, general foreman in the Building Trades, senior construction engineer and electrical manager at a nuclear power station, and station construction manager for NSTAR.

Randy Cox is the sales and support manager for Kelman, North America. His current duties include the sale and technical support of Kelman’s PROFILE P2 Operator Analyzer for North America. Prior to being employed by Kelman, Cox was employed by TXU Electric Delivery in the Dallas District as the Diagnostic Technician Supervisor. While employed by the utility Cox was the chairperson for the Oil and SF6 Diagnostics Committee, as well as the Chairperson for the Diagnostic Training Committee.

During the conference, Kelman will be exhibiting at The Hospitality Expo each evening in Booth #63