We perform routine protective relay calibrations, replacements, and upgrades. Numerous times during routine testing, it becomes apparent that the settings aren't correct. IET has the ability to provide engineering service to determine the proper set points and then update the relays for the new data. All wiring is done in a craftsman like manner with high quality terminations and terminal blocks. It is our policy to only use switchboard wire during these installations and use self-laminating wire labels on all terminations. At one location, 30 -351A SEL's were installed in switchgear. Below is a 587 SEL installation at a city utility which then followed with 2 more at other subs. The 587 is a transformer differential relay.

We also have a supply of surplus electro-mechanical relays that are in good condition that can be sup-plied quickly to support your needs.

SEL 351A prewired on a back panel to speed installation at a steel mill. Relay is mounted high for better visibility, the mounting panel was made with the relay tilted down. Includes isolation switches for future field testing.

Transformer differential relay installation at a city utility. This project allowed us to eliminate 7 electromechanical relays and re-place with 1 multi-function elec-tronic. The current transformers were rewired to a wye configura-tion on both sides of the trans-former. Isolation switches and the aluminum mounting panel were provided by the utility. AS this project continued to other substations, significant problems with the original wiring was found and corrected.