From software to relays, Utility Systems, Inc. ™ offers customers a variety of accessories to meet all digital fault locating and disturbance monitoring needs.

Model Ctr-1001

The USI CTR-1001 is a high accuracy solid-core current transformer for very low phase shift. These auxiliary CTs are useful in many monitoring applications such as Disturbance Monitoring Equipment (DME) and Digital Fault Recording (DFR) inputs as well as metering applications.


  • Turns Ratio: 1000:1
  • Rated Current: 100:0.1A
  • Phase Angle Error: <8 minutes from 1% to 100% or rated current
  • Secondary Open Protected: Voltage limited at 10V
  • Output: 25, 50, 125, 250, 375, or 500mV
  • Window Diameter (ID): 0.75”
  • Overall Diameter (OD): 2.25”
  • Width: 0.75”

Trip Indicating Relay (TIR)

Constructed inside a rugged, high-dielectric case with terminal studs that provide outstanding quality connections, the USI™ Trip Indicating Relay (TIR) is just one of several USI™ premier accessories. The USI™ TIR features millisecond actuation, high current capability, low resistance, and high switching capacity. While being both low cost and simple to install, the TIR has multiple functions including alarm indication, annunciation, event recording, breaker, relay, and communication.

A USI™ TIR is activated by sensing the presence of current in a trip coil. The trip coil handles extreme current overloads and features a high-speed contact closure time. Its special design is ideal for use with protective relays and circuits associated with DMEs (specifically the DFR application). To fit your company’s specific needs, USI™ TIRs are available in multiple arrangements, both pre-manufactured (Click the View Screenshots link below), and customer-specific.