GST has substantial experience with all types of end-to-end testing using both the Doble F6150 (at both ends) and the AVO MPRT (at both ends). Both test sets use a GPS clock to trigger at a specific time and can be used to simulate practically any event at both ends of the line. The benefits of end-to-end testing include the following:

• Discover incorrect settings that result in unexpected (nuisance) or inappropriate trips

• Determine transmission time delays that could result in coordination problems

• Verify the correct operation of all kinds of communications-assisted schemes

• Completely test the overall performance of a protection scheme with real secondary fault currents at each end

GST also has the ability to analyze the data created during these tests. We have the experience and equipment required to extract the oscillography from the relays and compare it against the expected results. We can then verify correct timing down to a fraction of a cycle. These services allow the customer to have a history of how the relay should react during certain faults (Zone 1, Zone 2, Reverse, etc.). With this knowledge, the customer can react quickly and confidently to determine the cause of a fault and reenergize the line.