PLANT MAINTENANCE

Maintenance of the facility electrical system is a key part of any serious energy-management effort. Perform the following steps on a regular basis:

• Measure the current drawn on distribution cables. Document the measurements so that a history of power demand can be compiled.

• Check terminal and splice connections to make sure they are tight.

• Check power-system cables for excessive heating.

• Check cables for insulation problems.

• Clean switchboard and circuit-breaker panels.

• Measure the phase-to-phase load balance at the utility service entrance. Load imbalance can result in inefficient use of ac power.

• Measure and chart the power factor of the load. Develop and post a simplified one-line schematic of the entire power network as well as other building systems, including heating, air conditioning, security, and alarm functions. A mimic board is helpful in this process. Construct the mimic board control panel so that it depicts the entire ac power-distribution system.
The board should have active indicators that show what loads or circuit breakers are turned on or off, what functions have been disabled, and key operating parameters, including input voltage, load current, and total kVA demand. Safety considerations require that machinery not be activated from the mimic board. Permit machinery to be energized only at the apparatus. As an alternative, remote control of machines can be provided, if a remote/local control switch is provided at the apparatus.

Environmental control systems should be monitored closely. Air-conditioning, heating, and ventilation systems often represent a significant portion of the power load of a facility. Computer-based data logging equipment with process control capability can be of considerable help in monitoring the condition of the equipment. The logger can be programmed to record all pertinent values periodically and to report abnormal conditions.