First Trip Analysis

Presented by:Steven Cannon, Substation Lineman

Chugach Electric

Chugach Overview• Alaska’s largest electrical utility • Provides generation, transmission, and

distribution services• Generation mix 90% gas, 10% hydro• 65,000 members

Chugach System

• 230kv-12.4kv lines• 50 substations and switchyards• 87 power transformers• 323 circuit breakers

Alaskan Rail Belt• The Alaska Railbelt system

– Electrically Islanded• The Railbelt system

– 850 MW Peak – Four generation areas:

Fairbanks, Anchorage, Beluga, and the Kenai Peninsula.

• The Anchorage area – Anchorage and Beluga

generation – Tied to both the Fairbanks and

Kenai Peninsula systems through single transmission ties

– 138 kV tie north to Fairbanks– 115 kV tie south to the Kenai.

Why First Trip Analysis?

• Analyze breakers “in the field” condition

Lubrication• Grease is composed of soap and oil• Oil provides lubrication• Soap gives consistency to hold lubrication• Oil eventually separates from the soap• Time causes soap to harden and gum up• Harden soap slows down breakers

Advantages of Capturing First Trip

• Breaker can be tested in energized state• Test can be performed in about 10 minutes• Overlay breaker operations

Qualifications for Operator

• Know how to read breaker control schemes• Be qualified to switch• Be computer literate• Understand safety rules for working in a

substation

ConnectionsCB Analyzer Hookup

• Insight into condition of a circuit breaker’s bearings, lubrication, trip and close circuits, auxiliary switch, main contact speed, DC supply and tailspring adjustment.

TRIP COIL PLUNGER

LATCH

Interpreting Graphs

Breaker 1616

Breaker 1616 DC Prints

DC (-)

DC (+)

TC Amp Probe

CC Amp Probe

DC LEADS

CT LEADS

Main Bearings

Latch Bearing

Breaker 1616 Results

Important Tips• Change batteries often• Come to the breaker prepared• Label wires to apply leads• Catch the first trip• Catch multiple breaker operations• Save each shot before moving the Profile• Periodically upload shots to computer• Develop a backup plan

Questions?