The market of instrumentation currently offers a large range of instruments for measuring the transient resistances of contacts that differ in the principle of operation, metrology characteristics, degree of automation, size, weight, and price.
For revealing the causes of LTC failures and for automation of the diagnosis the SKB EP Company entered the instrumentation market with the PKR-2 and PKR-2M instruments for the transformer LTS testing. Their main function is recording the oscillograms of contators operation and the circular diagram across all the phases at a time.
According to codes, LPC tests shall mandatorily include tests of the operation sequence of switching device contactor versus the angle of shaft drive turn, in other words, they require circular diagrams recording.
During installation and adjustment of HV circuit breakers, switch gears (KRUE, KRU, KRUN, and KSO) and in the course of their subsequent maintenance their rated characteristics need to be tested, namely, time, speed, travel, current and voltage.