Power Quality

Electrical Disturbance Log

The electrical disturbance log is the most important element that a customer can provide to the utility when you suspect a problem. Without a log, the power quality engineer may not be able to systematically and quickly uncover important information that could expedite finding the source of the problem.

The following items are the essential parts of a basic electrical disturbance log:

  • Time of Occurrence - What was the date and time of each electrical disturbance?
  • Equipment Affected - What equipment was adversely affected, and what were the consequences? Note any equipment failures or data losses.
  • Length of Outage - Document the length of the outage in one of three ways: shorter than two seconds, two to 120 seconds, or longer than two minutes. This will help identify what type of electrical disturbance occurred.
  • Weather Conditions - Note the temperature and any special weather conditions such as wind, lightning, or rain.

An example of an electrical disturbance log is shown below:

DateTime (AM/PM)Equipment Affected and DescriptionLength of Outage (Under 2 sec)(2-120 sec) (Over 2 min)Weather ConditionsReported By
7/10/01 6:45AM Building AC chiller tripped off-line none 70s, light wind Bill
7/10/01 7:15PM Building AC chiller tripped off-line none 80, 10-15mph wind, light rain Pete
7/12/01 6:15AM Building AC chiller tripped off-line 1/2 sec 72 deg, calm winds Harru
7/13/01 7:45AM Building AC chiller tripped off-line none 78 deg, 10-15 mph wind Bill
17/15/01 6:30AM Building AC chiller tripped off-line none 72 deg, light wind Bill

Please keep in mind that this log is the most important element to help identify the cause of the equipment malfunctions. Record information as soon as possible after a disturbance as accurate information will provide valuable clues toward a solution.