Description
Multifunctional earthing and soil resistivity meter
The Sonel MRU-200 earth resistance and soil resistivity
meter for earth resistance and soil resistivity measurements
with the use of various methods.
The feature that definitely distinguishes this model from other
meters of this kind is the use of all known methods of earth
resistance measurement. The measurement can be carried out using the
technical 3-pole and 4-wire method, also with additional clamps
(multiple earthing), as well as the two-clamp method and the impulse
method (earthing impedance measurement).
The use of the two-probe method allows the testing to be carried out
without the need for additional auxiliary probes which are driven
into the ground. The impact method, on the other hand, is used,
among other things, to diagnose lightning protection earthing. It is
also used for extensive, multiple and bonded earthing measurements
(also underground). The advantage of this method is that there is no
need to tamper with the circuit. The impact method enables
measurements to be made in accordance with EN 62305 - the need to
measure earth impedance.
This is not the end of the extended capabilities provided by the
Sonel MRU-200 meter. The device additionally has the function of
measuring the resistivity of soil, the continuity of protective and
equalising connections, and, with the use of clamps, also leakage or
fault currents.
Apart from the large number of functions and
many measurement
possibilities, the MRU-200 meter deserves recognition also for the
high accuracy of the obtained results. Measuring range -
measurements in accordance with EN 61557 - from as low as 0.30 Ω.
Sonel MRU-200 XL3 comes with XL-3 hard carrying case.
Measurement methods
- Impulse method - measurement of
lightning
protection systems with a measuring impulse ramp of 4/10 μs,
8/20 μs, 10/350 μs
- >3-pole and 4-wire method -
measurement of
earthing systems using auxiliary probes
- 3-pole method with clamp - measurement
of
earthing systems with multiple earth electrodes
- Two-clamp method - measurement of
earthing
system when the auxiliary probes cannot be used
- Earth resistivity - Wenner
method
- Resistance of earth and compensatory
conductors measured using current ≥200 mA with
auto-zero
function - meets the requirements of EN 61557-4
- Measurement of leakage current
Additional features
- Measurement of resistance of auxiliary
electrodes RS and RH
- Measurement of interference voltage
- Measurement of interference frequency
- Measurement in the presence of interference
voltage generated by power networks with frequency of 16 2/3
Hz, 50 Hz, 60 Hz, 400 Hz
- Selection of maximum measuring voltage (25 V
and 50 V)
- Automatic calculation of soil resistivity in
ohm-meters (Ωm) and ohm-feet (Ωft)
- Memory of 990 measurement results (10 banks
of 99 cells each)
- Calibration of clamp used
- Real time clock (RTC)
- Data transmission to the computer and mobile
devices
- Battery indication
Application
MRU-200 meter was
created for the most difficult working conditions. It
generates a
measuring current exceeding 200 mA, which provides effective
measurements of grounding of energy objects such as transformer
stations and power stations.
Thanks to the methods using clamps, it is not necessary to
disconnect the control connectors, which is sometimes a very
tedious
operation. This plays a special role when performing works on
objects exposed to weather conditions, where the connecting elements
are sometimes corroded or tarnished.
The graphical user interface provides clear readings and explicit
messages. This translates into quick, trouble-free service.
Impulse method
MRU-200 may be
used to test earthing of lightning protection systems, as
this meter
is able to simulate the conditions occurring during a lightning
strike - it generates current with a standardized pulse leading edge
and a time to half-peak. Available impulse ramps include 4/10
μs,
8/20 μs, 10/350 μs.
Compatible with ERP-1 adapter
ERP-1 adapter
allows user to test earthing systems using flexible clamps. This is
particularly useful, e.g. in case of lattice towers – there is no
need to switch off the line or disconnect control connectors.
Proprietary algorithm allows user to check the current direction in
the individual measurements and facilitates damage detections, e.g.
corroded steel strip (hoop).
Capabilities
The measuring
methods available in the device allow for comprehensive control of
working and protective grounding. The calibration function of the
test leads eliminates the influence of their resistance on the
result. However, this is just the beginning.
- The four-lead method provides very accurate
measurement of the expected small values of resistance –
eliminates the resistance of the test leads connecting the
meter to grounding.
- Measurement of the continuity of protective
connections and equipotential bondings with a current
exceeding 200 mA meets the requirements of EN 61557-4
standard.
- Before performing the measurement, the meter
checks whether the tested object is a subject to excessive
interference voltage, which may indicate additional
problems
Memory and results
The results can
be saved to the device's memory. It is divided into 10 banks of
99
cells, each corresponding to one measurement. These results
can be
easily transferred to the Sonel Reader software for archiving
or
subsequent analysis and research.
Bluetooth wireless interface may be used to transfer
measurement
results to PC software or to a mobile phone with dedicated app -
Sonel MRU Mobile. This provides not only data archiving
function,
but further data transfer - directly from the measurement site via
an e-mail.
