GISmonitor partial discharge monitoring system
Parallel UHF PD measurement on all channels
Parallel monitoring of all PD sensors in one or even multiple GIS
Compatible with all UHF sensors for GIS systems
Suits all currently known ultra high frequency (UHF) sensors available on the market for GIS systems
Real-time PD acquisition and analysis
Detects any UHF signal and digitises within microseconds
Parallel readings
Measures PD peak values, PD scope amplitudes, and PD patterns
Automatic noise separation techniques via intelligent software analysis
A separation of PD events from external disturbances or internal switching pulses is provided by the advanced GISmonitor software
About the product
The main task of the GISmonitor partial discharge monitoring system is to detect internal partial discharge (PD) in the insulation system of gas-insulated switchgear (GIS). The system's hardware has been optimised for parallel, real-time PD acquisition on multiple channels.
Each 8-channel acquisition plug-in board operates independently, but can be combined with a nearly unlimited number of units to monitor all PD sensors, in parallel, in one or multiple GIS systems. The unit detects and digitises any ultra-high frequency (UHF) signals within microseconds. Therefore, no PD activity is left undetected. A separation of PD events from external disturbances or internal switching pulses is calculated in real-time; this provides automatic, effective PD detection and alarm.
The GISmonitor is designed to suit all currently available UHF sensors for GIS PD monitoring, including embedded and externally retrofitted UHF sensors. A special input protection unit (IPU2) blocks strong transients (VFT). The pre-processing unit FCU2 demodulates UHF signals into a lower frequency band for easy transmission over longer distances.
The common software interface allows you to easily monitor PD activity on the entire GIS system without interrupting its operation. All data is collected, stored, and automatically analysed in one central server and a database of typical PD failures is provided (ICMexpert software). External interfaces to IEC 61850, SCADA, or other overall monitoring systems are available on request.
To receive software updates or user guides, please contact [email protected] or call +49 241 74927. Please have your device serial number ready or state your reason for interest.
FAQ / Frequently Asked Questions
Certain features set the GISmonitor apart in its abilities as a specific PD monitoring system for GIS. These differentiating features include:
- The unit accommodates a customised system layout for each installation. Flexible system design due to frequency conversion -> up to 80 m of sensor cabling.
- Advanced software features for sensitivity verification and high voltage testing.
- High levels of redundancy and self-monitoring.
- Highest cyber security standards (hardened system, encrypted communication, user authentication, integration to superordinate systems).
- Continuous and parallel PD measurement on all channels -> no PD pulse gets lost.
- All PD measurement data is saved, facilitating an in-depth review and analysis.
More features often necessitate more hardware. When choosing between multiple PD monitoring systems for your GIS, look closely at the prospective systems' specific capabilities to ensure they are comparable.
The detection of the problem is done by the GISmonitor system autonomously. You will not be required to determine if there is PD activity. The software algorithm continuously analyses all measured data and detects whether PD activity is present. Regarding a deep analysis of a PD defect, our ICMexpert software comes with a database of known defects. The software automatically takes the phase resolved partial discharge (PRPD) that triggers an alarm, compares it to a database of known defects, and finds the best match within our database. Accordingly, it will give you an indication of the most likely type of defect you are facing.
The GISmonitor is based on a scalable architecture. The number of channels can be increased by adding more acquisition cards and, if required, more Partial Discharge Monitoring Acquisition Racks (PDMAR). With this approach, systems with more than 1000 channels are possible, and a system design customised and optimised for a specific GIS can be provided.
Furthermore, a permanent PD monitoring system provides an instant indication in case PD activity occurs. Manual measurements with a portable instrument can be weeks or months apart, possibly delaying detection after PD's inception.
Further reading and webinars
Related products
Troubleshooting
Check that the power is on for the cabinet and make sure there is power to the plug-in board.
- Make sure the cabling is properly connected.
- Check that the plug-in board is indicating that the initialisation is correct - green LED will be lit up if so
- Reset the alarm in the GISmonitor control software
Check the cabinet for damage or visual signs of any problems. Reactivate the MCB and reset the alarm in the GISmonitor control software.
You should:
- Bridge out the uninterrupted power supply (UPS) on the back of the cabinet.
- Measure the insulation resistance of the cabinet power supply.
- Disconnect all components from their terminals until the insulation resistance is acceptable. The criterion is R > 0.2 MΩ.
- If possible, reset the alarm in the GISmonitor control software (this depends on the component).
- Report the affected component to Power Diagnostix.
You should:
- Check that the power is on for all cabinets
- Check the switches on the hat rail of the cabinets to identify the open connection
- Ports 7 and 8 must show a green LED
- Check the FO cabling between the affected switches
- Repair the FO cable
- Check the system for normal operation
- Reset the alarm in the GISmonitor control software
The cabinet’s overvoltage (OV) protection module has activated, and it needs replacing.
You should:
- Check the cabinet for damage and adequate function
- Unplug the OV protection module
- Plug in a new module
- Reset the alarm in the GISmonitor control software
This means the uninterrupted power supply (UPS) is using the battery, due to a missing power supply.
You should:
- Check if the MCB has tripped
- Measure the power supply
- Check all cables to ensure the connections secure
- Reset the alarm in the GISmonitor control software
You should:
- Check the back of the UPS and find the thermal fuse
- Reset the thermal fuse by pressing the red button
- Test if the system has returned to normal functionality
- Reset the alarm in the GISmonitor control software
This message indicates that you must replace the UPS battery.
You should:
Contact the UPS manufacturer or Power Diagnostix for a new battery and follow the manufacturer’s battery replacement instructions.
Interpreting test results
The evaluation of a PRPD pattern, enables you to determine the kind of fault within the test object. Most partial discharge (PD) faults, such as insulation damages, voids, surface discharges, or floating points, will have completely different PD patterns. The typical criteria for classifying these patterns are:
- Phase position of the maximum partial discharge
- Phase position of the starting electron
- The gradient of discharges
- The shape of discharges in the positive and negative half-cycle
- The absolute value of discharge in pC or nC
- Short-time or continuous discharges
For successful interpretation, it is also necessary to get as much information as possible about the test object and its environment. Such information could include temperature, installation condition, age of the test object, previous faults, or weather conditions.
It is useful to store typical PD patterns of known faults in an archive. This, can be done by using the GISmonitor software in combination with Power Diagnostix’s ICMexpert software. This customer-specific database will be helpful for later evaluation on other test objects.
User guides and documents
FAQ / Frequently Asked Questions
The correct voltage depends on the type of GIS, the type of sensor, the measurement instrument, and the type of injector used. If we do not know that information for an asset, we can rely on experience with comparable assets. For example, if we know that info for one type of 400 kV GIS, we can use its resultant recommended impulse voltage for a similar GIS of another manufacturer. That will give a good indication even though it is impossible to prove it is 100 % correct. We do not, under all circumstances, have to perform a sensitivity check according to CIGRE. While this recommendation makes sense, applying a test that is not entirely covered by the CIGRE sensitivity definition still gives a good performance evaluation of our monitoring system, validating that it can pick up the signal. Whether that's a 5 % or 10 % signal cannot be stated explicitly. But we will have a rough estimation of the sensitivity of our system, and we will have verified that it is performing what it is supposed to do.
For the GISmonitor system to detect moisture within a switchgear, that moisture needs to have an impact on the electric field, leading to a local field increase and, after that, the inception of PD. Then, it can be detected. The system will not detect the presence of moisture alone because we are measuring an electrical signal.
The PDMS includes an extensive self-monitoring functionality that will detect most issues automatically. Any problem then raises a “Maintenance Request” or a “System Fault” indication to the operator. If the PDMS is integrated to any superordinate systems via one of the available interfaces, such notifications are forwarded automatically.
The commissioning of each PDMS includes a so-called ‘sensitivity verification’. This sensitivity verification proves that the PDMS can detect all PD defects above a certain amplitude (typically 5 %). The sensitivity verification can be based on, e.g., CIGRE TBA 654 recommendations.