IT Systems

Ground-fault location: The concept

How does a ground-fault location system work?

A ground-fault location system comprises a ground-fault test device and a ground-fault evaluator connected to one or more measuring current transformers. The ISOMETER® of the iso685 series features a built-in ground-fault test device.

Functional sequence
  • Start ground-fault location by activating the ground-fault test device ISOMETER®. 
  • The ground-fault test device briefly connects the live conductors to ground.
  • Electronic current limiting, this connection and the ground fault create a closed circuit, in which a test current is determined by the system voltage flows. The test current is limited to a maximum value.
  • The test current pulse flows from the ground-fault test device via the live conductors, the ground fault Rf and the ground wire (PE conductor) and back to the ground-fault test device.
  • The test current signal is detected by all measuring current transformers on the circuit and evaluated by EDS ground-fault evaluators.
  • The fault location can be identified using the assignment between measuring current transformers and circuit.
Automatic ground-fault location/permanently installed systems

The ground-fault monitoring device with built-in ground-fault test device, the ground-fault evaluator and the associated measuring current transformers are components of the installation. Ground-fault location is started automatically by the ground-fault monitoring device.

Manual ground-fault location/portable systems

Manual ground-fault location can be implemented to meet the following requirements:

  1. In addition to permanently installed EDS systems, a portable ground-fault evaluator is used for ground-fault location in secondary outgoing circuits.
  2. If the installation does not have an ground-fault test device, a portable ground-fault test device is used.
  3. If the IT system has been de-energized, a portable ground-fault test device with built-in measuring voltage source is used.
Distinguishing features of main circuit/control circuit

The essential difference in the two applications is in the significantly reduced test current for application in control circuits and/or the response sensitivity.

Characteristics of switching function
Advantages of ground-fault location with the EDS system
Resistance grounding has several advantages over solid grounding:
Optimized maintenance
  • Ground-fault location without disconnecting the electrical installation
  • Selective fault location by fast and precise localization of the faulty sub circuit
  • Centralized indication and operation with LC text display
  • Reduced maintenance costs
Increased operating reliability
  • Electrical installations are kept at a high level of availability
  • Increased productivity because interruptions to operation are avoided
  • More comfort for customers (service area)
Improved economic efficiency
  • Time and costs for maintenance are reduced
  • Weak points in the installation are recognized
Flexible and configurable solutions
  • Cost-effective construction by modular system components
  • Measuring current transformers are available in different sizes and shapes (round, rectangular, split core, flexible)

Downloads

CategoryNameSizeLanguageTimestampD-/B-Number
Product Overviews Electrical Safety 6.4 MB EN2022/05/25 08:08:1125.05.2022 08:08:11
Technical Information 2020 Guidelines (US) 5.6 MB EN2020/01/28 14:33:1428.01.2020 14:33:14

Products

Ground-Fault Monitoring, Ungrounded

ISOMETER® iso685…
ISOMETER® iso685 Series

Ground-fault detector for ungrounded AC/DC systems

Ground-Fault Location, Ungrounded

ISOSCAN® EDS440
ISOSCAN® EDS440 Series

Ground-fault location module for ungrounded AC/DC systems

Ground-Fault Monitoring, Ungrounded

ISOMETER® iso685…
ISOMETER® iso685 Series

Ground-fault detector for ungrounded AC/DC systems

Details

Ground-Fault Location, Ungrounded

ISOSCAN® EDS440
ISOSCAN® EDS440 Series

Ground-fault location module for ungrounded AC/DC systems

Details