Atec Megger-MRCT - Manual (Page 2)

MRCT
Megger Relay and Current Transformer Test Set
For example, if 1 volt per turn is applied to the secondary winding,
the voltage present on the primary winding would be 1 volt. More
specifically, if 120 volts were applied to the secondary of a 600:5
current transformer (120:1 ratio), 1 volt would be present on the
primary winding.
Winding resistance Test
Measures CT winding resistance with the injection of a test
voltage, measuring the DC current and calculating temperature
compensated resistance.
Demagnetization
Normal operating conditions and typical winding resistance
measurements can cause a CT to become magnetized. The MRCT
has the ability to automatically demagnetize the CT under test. This
automatic demagnetization routine is useful to ensure that the CT
saturation test yield correct results. Prior to testing demagnetization
is recommended per ANSI C57.13.1.
CT Burden
The MRCT measures the connected CT burden load with direct
injection of secondary current to a load that is disconnected from
the CT. The MRCT measures the secondary voltage in magnitude
and angle of the connected burden in VA and power factor.
Insulation resistance Test
In order to ensure that the CT secondary wiring is properly insulated,
the MRCT system includes a 500 V, 1,000 V insulation resistance
test system. This test ensures that the CT secondary winding and
secondary wiring is properly insulated per ANSI C57.13.1.
The MRCT will also automatically switch the test leads to perform all
required insulation test. These test include H-L, H-G, L-G.
Note: Disconnect all electronic loads before performing this test.
Data Storage and printing
The MRCT test system not only permits accurate and automated CT
testing, but also catalogs and stores test results within the STVI for
simple retrieval by software at a later date. All cataloged test results
can be uploaded to Megger’s PowerDB
TM Lite for report generation
and saturation curve plotting on a computer or STVI. PowerDB
Lite also has the ability to operate the MRCT with no operator
intervention, thus providing a completely computer controlled
automated test system.
Upgradeability
The MRCT includes the ability to upgrade testing capability. With
various configurations and accessories the MRCT system can be
upgraded as new testing needs are developed.
FeATUreS AnD BeneFITS
■ ■ Industry leading test duration using patented simultaneous
multi tap measurements - The MRCT system can provide
concurrent measurement of voltages on all taps during CT
saturation, and ratio and polarity testing. This allows the MRCT
system to calculate the knee points and ratios of all windings at
the same time thus eliminating the need for multiple tests on a
CT. This will drastically reduce testing time.
■ ■ Automated Test Plans with CT Saturation, Ratio and
Polarity, Winding Resistance and Insulation Testing - The
microprocessor controlled output fully automates testing of CTs.
The MRCT will directly connect to multi ratio CTs and perform
all tests – saturation, ratio and polarity, winding resistance, and
insulation – on all taps with the push of a button and without
changing leads.
■ ■ Direct Connection to Multi Ratio CTs - The MRCT will directly
connect to all taps on multi ratio CTs to eliminate lead changes
required to test all inner-winding CT ratios, saturation curves and
knee points. The MRCT will test all programmed taps with the
push of one button.
■ ■ Full Color, High Resolution, LCD Touch Screen - Menu screens
and touch screen function buttons are provided to quickly and
easily select the desired test function. Tests results can be saved
to the unit for download to a memory stick to transfer or print
test reports.
■ ■ CT Saturation, Ratio and Polarity, Winding Resistance, and
Insulation Automated Testing - The microprocessor-controlled
output fully automates testing of CTs. This automated testing
simplifies CT testing and reduces testing time. Automated testing
is accomplished directly on the Megger’s STVI or via PowerDB
Lite.
■ ■ CT Demagnetization - During operation and routine
DC winding resistance testing, it is possible for a CT to
become magnetized. The MRCT includes an automated CT
demagnetization function, which allows determination of
accurate knee point and ratios thus providing stable, repeatable
test results, and reduces test time.
■ ■ Insulation Test - The MRCT includes a 500/1,000 V insulation
test system to verify the CT secondary winding and secondary
wiring. This insures that the secondary insulation has not
degraded and will continue to perform its function during high
current faults.
■ ■ Test Result Report - The MRCT offers storage of complete test
files in an easy-to-use, versatile format that permits upload to
PowerDB Lite, or printing test results using the optional external
printer. These options provide a simple, complete, easy way to
store over 200 test results and saturation curves. All test results
can be cataloged and stored in the MRCT.
The MRCT is available in 2 onboard display/enclosure options.