Measurements of the insulation and the area of damage
A trustworthy equipment to measure insulation resistance up to 20 T is the Sonel MIC-5050 insulation resistance meter. The device is intended for use in control tests of AC power networks’ electric shock protection. It is utilized to conduct measurements whose outcomes define the installation’s level of safety.
For electric power services that check the condition of electro insulating materials, the meter is advised.
Application
MIC-5050 meter is designed to measure the insulation resistance of electro-power objects, i.e. single- and multi-core cables, transformers, motors and generators, capacitors, switches and other devices installed in power stations. Furthermore, it is dedicated for measurements in areas with very high electromagnetic disturbances, e.g. electrical substations with 765 kV voltage or higher.
Capabilities
Highly efficient HV inverter, with test voltage of 5 kV and current of 6 mA, suitable for measuring the insulation resistance up to 20 TΩ. Achieving such a result makes these meters unrivalled devices. Three-wire resistance measurement, performed using a “GUARD” wire, eliminates surface leakage currents caused by contaminated insulation, thereby increasing the reliability of obtained results.
The meter measures temperature of tested object, which is necessary to determine the temperature correction factor for RISO. In addition, it indicates the absorption coefficient (DAR – Dielectric Absorption Ratio), Polarization Index (PI) and the value of Dielectric Discharge (DD). The device allows user to assess the condition of the insulation, by applying the test voltage incrementally in steps (SV). This solution ensures that a dielectric in good condition will provide the same results, regardless of the applied voltage. Deviations in obtained resistance values of approx. 25%, observed on the chart in the individual steps, may indicate the potential insulation defects.
MIC-5050 has the unique ability to perform measurements on multi-core cables, within one connection step, using the AutoISO-5000 adapter. This solution reduces the duration of measurements on repetitive of objects, such as cables of street lighting systems. Inverter with a power of almost 30 W is able to intensify the point of cable damage, which facilitates finding the location of the fault using a reflectometric method e.g. with TDR-420 device.
Built-in digital filters, with averaging time of 10, 30, 60, 100, 200 sec. and “smart” solution guarantee stable measurement results in areas of strong electromagnetic interference.
Data analysis
The device, with its backlight graphical screen may display a waveform of insulation resistance, voltage and current as a function of time. The operator, basing on the trend shown by the waveform, may quickly assess the insulation condition right after starting the measurement. This provides full control over the tested object and clear image of the tested insulation. In addition, with movable tags, the operator may trace the course of the measurement and check resistance values obtained for any time of the current measurement and of measurements made in the past.
After installing mobile application, as a part of the set the user receives Sonel Reader software for collecting historical data and comparing it with current results, transferred from the extensive memory of the meter. This solution helps user to prepare a measurements report, track the insulation degradation and plan the maintenance / repair works.
