CT Replacement Initiates Substation Makeover
Folsom, Calif. – When lightning struck the substation at Arvin-Edison Water District’s Forest Frick pump station, it not only destroyed the Current Transformer (CT), it also sparked a project to refurbish critical infrastructure responsible for pumping water to farmers and communities in Kern County, California.
The damaged CT, along with other wear, was identified during an annual inspection. Additionally, the CT was owned by an entity that is no longer contracted to provide power to this pump station. To address both the electrical and business issues, Arvin-Edison decided to replace the CTs and VTs with new devices.
“Trimark serves the entire value chain of metering from instrument transformers to measuring devices to the presentation of accurate, timely data required for business and operational decisions,” said Mark Morosky, Trimark President and CEO. “By overseeing the installation of these instruments, we supported Arvin-Edison’s aim to accurately measure their power consumption.”
As primary contractor for the replacement, Trimark was responsible for the entire project including assessment and planning; equipment specification; project cost estimation; removal of the old CTs and Voltage Transformers (VTs); redesign and modification of the substation lattice structure; installation of combined transformer units; and installation and configuration of a new load meter.
The project required coordination and cooperation between Arvin-Edison, the District’s Engineer, PG&E, Trimark, and Delta Testing, an electrical and construction subcontractor.
During the project, Arvin-Edison prioritized selection of CTs with extended life expectancy. Ultimately they selected iTEC’s stainless steel unit with combined CT-VT capability. Trimark estimates the potential lifespan on these devices at 50+ years.
The substation bay was originally designed to hold shorter CTs. Moreover the installation required room to maneuver the crane head and block required to lift each of the three, 2100 lb. units. In order to accommodate the height of the new devices, the decision was made to lower and remount the cross member four feet below its original position. Trimark managed the design and guided the team, including Arvin Edison’s site engineer, the electrical engineer, and structural engineer, to concur on the change.
The new design also specified moving the lightning arresters to a more effective position closer to the CT. Trimark’s recommendation was intended to mitigate a common cause of CT failure.
While the heavy lifting was occurring outside, inside the control building Trimark replaced an old meter with a new, ION 8650 switchboard meter and connected it to a Metrum Wireless modem. This portion of the project included relocating the meter out of switchgear that is scheduled for future upgrades. This new configuration enables remote meter interrogation. The metering portion of the project also included connecting the new CT-VT leads to the load meter, meter configuration, meter testing, commissioning, wiring verification, meter programming and burden testing.