Description
Multifunctional earthing and soil resistivity meter
The Sonel MRU-200-GPS earth resistance and soil resistivity
meter is a versatile meter for earth resistance and soil
resistivity measurements. The device allows the use of all known
earth resistance measurement methods. This renders it an unrivalled
measuring instrument in its category and definitely makes it stand
out from other devices of its kind. Sonel MRU-200-GPS allows you to
perform tests with the 3-pole and 4-wire method, using additional
clamps (multiple earthing), as well as the two-clamp method and
impulse method (earth impedance measurement).
The application of the two-core measurement method allows, under
certain conditions, to perform earth resistance measurements without
the use of auxiliary probes which are driven into the ground. The
impact method, on the other hand, is used for diagnosing lightning
protection earthing, but can also be used to measure extensive,
multiple and connected earthing (including underground) without
interfering with the circuit. With the use of the impact method it
is possible to carry out measurements in accordance with EN 62305 -
the need to measure earth impedance. It is worth noting that the
instrument also has a built-in GPS receiver, which allows for
recording the result along with the coordinates of the location. An
additional function of the meter is the possibility of carrying out
measurements of soil resistivity, continuity of protective and
equalising connections and, with the use of clamps, also leakage or
fault currents.
Additional features
- Built-in GPS receiver – recording
results with location coordinates
- 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-GPS 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-GPS 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.
