Dear Ms. Tucker,
This letter is a follow up to the article in the November 2017 issue, “Is Your Pumping Station Power-Proofed?”
Years ago, I led a team that was tasked with designing and managing construction of a two-way wireless communications network for a gas and electric utility that covered 2,500 square miles, in two states, and was divided into six divisions that normally would be separated for their communications. In emergency situations, they would need to talk across division lines and or have vehicles move between divisions. One of the major criteria was that the system had to operate during power interruptions. We chose to install eight hours of battery backup because it was seamless to the equipment, and with remote sites, it was less maintenance-intensive than backup generators.
Since the equipment was high-power radio transceivers that generated a great deal of heat, each cabinet was equipped with a cooling fan and each enclosure had air conditioning. We used DC-powered fans and included that load on the battery backup system but not the air conditioning. The battery chargers that we used produced quality voltage that would allow them to power the transceivers directly if the batteries had to be taken out of service for maintenance. This system served that utility for a number of years, and as improvements to the communications system were available, they could be added by upgrading rather than replacing the entire system.
At the time of this design and installation, this was quite innovative and saved our equipment from failure many times.
I know there have been many improvements in chargers and batteries, and our system would be considered very outdated now.
I just thought you might be interested in some information from the past.
Harold A. Schwartz, P.E., Fellow NAFE