Megger’s New MRCT Test Set Cuts CT Test Time By 20%!
- Published: Tuesday, 06 March 2018 07:42
A patented technique that allows simultaneous testing on all taps means that Megger’s new MRCT test set can cut the time needed to test current transformers (CTs) by up to 20% compared with conventional test sets.
This innovative instrument also offers enhanced measuring accuracy to support the testing of metering-class CTs and it can now optionally be supplied with a DC excitation feature that allows CTs with knee points up to 30 kV to be tested. Facilities for testing single-phase protection relays can also be specified as an additional option.
MRCT test sets are available for use with the Megger STVI touch-screen interface, which has a large high-resolution colour display, or with a standard laptop running Megger’s renowned PowerDB software. It is the smallest and lightest 2 kV test set of its type currently available, and is capable of performing simultaneous measurements on up to 10 taps.
The test set connects directly to multi-ratio CTs and, at the push of a button, automatically performs a comprehensive sequence of tests, including saturation, ratio, polarity, winding resistance and insulation, thereby providing further time savings. No changes of connections are needed during the test sequence.
Grouped testing is supported with automatic demagnetisation and calculation of ratio errors, knee points and saturation curves. For CTs with knee points up to 2 kV, AC excitation is used to saturate the core during testing. For CTs with higher knee point voltages, up to a maximum of 30 kV, the MRCT can optionally be supplied with facilities for DC excitation. When this is used, the results obtained are automatically converted to their AC equivalent. The MRCT also offers insulation resistance testing at 500 V and 1,000 V.
In addition to facilities for automatic testing of single- and multi-ratio CTs of all types, the MRCT test set also makes extensive provision for manual CT testing. The results from both automatic and manual tests can be stored in a high-capacity internal memory for subsequent download to a PC running PowerDB, which provides a wide range of reporting options.
As an option, MRCT test sets can be configured to include the functionality needed to test most commonly used types of single-phase protection relay. When used in this way, the instrument offers a current channel rated at up to 30 A at 200 VA continuous and up to 60 A at 300 VA for short periods. The voltage channel can provide a variable output of 0 to 30/150/300 V at 150 VA or can be configured as a second current channel to allow the testing of differential relays.