Check the current and potential transformers and the disconnect switches for
manual operation annually.
Check the transformer tank, cooling fins, tubes, radiators, and all gasketed and
other openings visually for any possible leaks monthly.
Check the gauges on the transformer for oil level, oil temperature, and tank
pressure weekly. Look for signs of overheating or corrosion.
Observe any change in operating sound regularly. A louder hum than normal
could indicate low oil level or temperature rise inside the tank.
(c) Dry Type Transformers:
Retorque connections, vacuum out dirt, and blow with a maximum of 25 psi
compressed air every two years.
Check temperature and cleanliness weekly. Look for signs of overheating or
220.127.116.11 Voltage Regulators. The following represents a maintenance checklist for voltage
regulators. Each item should be spot checked on a periodic basis to ensure proper function:
(a) Check for physical damage to the tank periodically.
(b) Check the connections.
(c) Check the operation lever setting for boosting and bucking voltage.
(d) Check the accuracy of the regulator by checking the voltage across the bus with the
help of a voltmeter.
18.104.22.168 Switches. There are several different types of switches on line and on the
substation busses. The primary function of a switch is to open or close a feeder.
(a) Check for loose connections and proper operation biannually.
(b) Check contact surfaces biannually.
22.214.171.124 Circuit Breakers. The following represents a maintenance checklist for low
voltage and high voltage circuit breakers. Each item should be checked every three years for low
voltage circuit breakers, every two years for high voltage circuit breakers, and annually for high
voltage circuit breakers used in generating stations.
(a) Check mechanical and electrical operation and alignment.