Atec MRCT User Manual

Megger Relay and Current Transformer Test Set

MRCT

Megger Relay and Current Transformer Test Set

 Industry leading test duration using patented

simultaneous multi-tap measurements reduces
testing time by 20% on multi-tap CT’s

 Increased measurement accuracy to support

metering class CT testing

 Smallest and lightest 2 kV secondary voltage

injection unit on the market

 Integrated single phase relay test system

 General purpose substation secondary circuit

testing with 300 V & 60 A generators

 Grouped testing: demagnetization, knee

points, ratios, saturation curves, and more

 Measure all ratio’s and saturation curves on

multi-tap CT’s with one lead connection

 Built-in insulation resistance testing

MRCT

DESCRIPTION

The Megger MRCT is a light weight, robust, portable unit
used to perform demagnetization, ratio, saturation, winding
resistance, polarity, phase deviation, and insulation tests on
current transformers. The MRCT automatically calculates ratio
errors, saturation curves, and knee points. The MRCT provides a
microprocessor-controlled variable voltage and current output and
precision instrumentation for automatically testing single and multi
ratio CTs, reducing testing time and increasing productivity. The
MRCT will directly connect to multi ratio CT’s 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.

The MRCT can be controlled
via Megger’s Smart Touch
View Interface (STVI)
controller. The STVI controller
is a full color, high resolution,
LCD touch screen which
allows the user to perform
manual and automatic testing
quickly and easily using the
manual test screen, as well
as using pre-constructed
test routines. The large color
display permits the user to easily read all pertinent data while the
test is being performed and provides the ability to view the current
transformer’s saturation curve. The unit can also be configured to
come without a Megger STVI and can be controlled via a laptop
with Megger’s PowerDB software.

Current transformers can be tested in their equipment
configuration, such as being mounted in transformers, oil circuit
breakers or switchgear. It is necessary for the equipment to be
completely isolated from the electrical system prior to testing.

APPLICATIONS

Saturation Test

With the single push
of a button, the
MRCT performs a
CT saturation test
and calculates the
rated knee point. The
saturation test can be
performed at frequency
of 50 or 60 Hz up to
2,000 volts as required
by IEC regulations.

The MRCT will calculate the rated knee point in compliance with
IEEE C57.13.1, IEC 60044-1 or IEC 60044-6 on both standards as
well as of specialized CTs such as PX, TPS, TPX, TPY and TPZ. While
the saturation test is being performed, the MCRT will plot the CT
saturation curve on the STVI display and automatically provide the
user with the rated knee point per the desired IEEE or IEC standard.
Many substations CTs include a multi-ratio secondary; therefore the
MRCT has the ability to plot and simultaneously display up to 10 CT
saturation curves.

Ratio, Polarity Test

Ratio testing can be performed by using the MRCT. The method
used by the MRCT compares a voltage applied to the secondary
winding to the resulting voltage produced on the primary winding.

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.

MRCT

Megger Relay and Current Transformer Test Set

The MRCT is available in 2 onboard display/enclosure options.

 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.

MRCT

Megger Relay and Current Transformer Test Set

SPECIFICATIONS

Input

Output

Voltage Continuously variable in three ranges:

Current

Output Current Power Max V/Duty Cycle

30 Amperes 200 VA (282 peak) 6.67 V rms

60 Amperes 600 VA 90 cycles

Instrumentation

Voltmeters

Output

Resolution 0.0000 to 1.9999/19.999/199.99/1999.9

Ranges 0 to 2/20/200/2000 V

Accuracy ±0.5% of reading typical

Input

Primary Voltage
Measurement

Ranges 0 to 0.35/2.0/20.0/200.0/600.0 V

Resolution 0.0001 to 1.9999/19.999/199.9/600 V

Accuracy ±0.02% of reading and ±.02% range typical

Secondary Voltage Measurement

Ranges 0 to 2/20.0/200.0/2000.0 V

Resolution 0.0000 to 19.999/199.9/1999.9 V

Accuracy 0 to 999.9 V

Ammeter

Output

Ranges 0.0 to 1.0/10.0/60.0 A

Resolution .001/.01

Input

Excitation curve testing

Range 0.0000 to 0.1/1.0/8.0 A

Accuracy ±0.08% of reading ±.08% range typical

100 to 132 V or 200 to 264 V, 1ø, 50 or 60 Hz,
15 A max.

0 to 30 V at 5.0 A max
(15 minute on, 5 minute off)
0 to 300 V at 1.0 A max
(15 minute on, 5 minute off)
300 to 2000 V at 1.0 A max
(5 minute on, 5 minute off)

(15 minutes on, 5 minutes off)

±1.0% of reading typical max

±0.05% of reading and ±05% range maximum

±0.02% of reading and ±.02% range typical
±0.05% of reading and ±.05% range maximum

1000 to 2000 V

±0.08% of reading and ±.08% range typical
±0.2% of reading and ±0.2% range maximum

±0.2% of reading ±0.2% range maximum

Phase Angle Measurement

3 digits

Range 0 to 360 degrees

Resolution 1 minute

Accuracy ±3 minuntes typical

±6 minutes maximum

Ratio

Secondary Voltage Injection Method

Range Accuracy

0.8 to 2000 ±0.02% typical
±0.05% maximum

2000 to 5000 ±0.03% typical
±0.1% maximum

5000 to 20000 ±0.05% typical
±0.2% maximum

Winding Resistance Test

Measuring Range 0 – 30 Ω

Accuracy (at 20° C) ±1%, 0 – 30 Ω

Insulation Test

Test Voltage 1000 VDC, 500 VDC

Measuring Range 20 GΩ, 10 GΩ

Short Circuit Current 1.5 mA nominal

Test Current on Load 1 mA at min. pass values of insulation

Accuracy 1000 volts ±3% ±2 digits ±0.2% per GΩ

Communication

(as specified in BS7671, HD 384 and IEC 364)

500 volts ±3% ±2 digits ±0.4% per GΩ

Ethernet

Interfaces

Environment

Operating -10º C to 50º C

Storage -30º C to 70º C

Enclosure The unit is housed in a rugged enclosure suitable

Standards

Dimensions

Weight

for use in outdoor substations.

IEC 61010, CSA 22.2, CE

14” H X 7.5” W X 12” D
(36 H X 19.3 W X 30.5 D cm)

36.7 lb (16.7 kg)