LiBo – detects and localizes arcs in gas-insulated switchgears

Arc detection based on optical sensors

The main task of the optoelectronic arc detection system (LiBo) is to locate arc faults in gas-insulated switchgear safely and accurately. In the event of an arc fault, only short interruptions to operation occur and the availability of the switchgear is increased.

For this purpose, light sensors monitor the individual gas compartments. If an arc occurs, the signal is transmitted via a fiber-optic cable to the electronic unit, which triggers a corresponding error message in the substation itself and in the SCADA system. As a result, affected gas compartments can be isolated immediately before significant damage can occur. With the precise localization of the fault down to a single gas compartment, appropriate measures can be taken immediately to restore uninterrupted operation. Any consequential damage during the switching process can be prevented by knowing the exact location of the defective gas compartments.

Use cases:
  • Testing / Commissioning
  • Monitoring
  • Maintenance / Repair
Arc detection schematic view

Schematic view of the LiBo system: the light sensors are connected to the electronic unit via fiber optic cables

Advantages of the optical monitoring of gas-insulated switchgear

Commissioning & Maintenance
  Exact localization of the arc down to the individual gas compartment
  Avoidance of dangerous switching operations (e.g.: disconnector switching to a faulty gas compartment (may damage the disconnector) )
  Reliable detection of flashovers in lightning impulse tests and HV testing
  Early detection of defects during HV test
  Fast recommissioning in the event of failure
  Very low maintenance requirements
  Compatible with any common switchgear
Regular operation
  Fast response time due to optical signal transmission and processing
  Short downtimes of the GIS in case of an arc fault due to precise localization of the faulty gas compartment
  No interference by electromagnetic sources (e.g. UHF signals, cell phones, switching devices, etc.)
  Additional gas compartments can be installed at any time
  Possibility of retrofitting existing GIS
LiBo sensor connected to GIS

The arc detection system can also be retrofitted to existing switchgear

Arc detection - control module

The signals are evaluated within a few milliseconds in the electronic unit

Arc detection with optical sensors on a gas-insulated switchgear system

The LiBo system has proven successful in more than 50,000 monitored gas compartments worldwide