Easy Location of Ground Faults in Live Ungrounded Power Systems

The National Electrical Code Article 250.21(B) and Canadian Electrical Code Rule 10-400 require ground-fault detection and alarm for ungrounded power systems.  An Insulation Monitoring Device (IMD) is the best solution for these systems.  Above and beyond the basic Code requirements, automatic ground-fault location can be implemented with the addition of EDS technology.
The inclusion of EDS adds value, saves time, and increases system performance through efficient ground fault location. 

What is EDS and how does it work?

EDS is used in combination with an IMD for the localization of insulation faults in ungrounded power supplies. An EDS system  includes an insulation fault evaluator connected to zero-sequence current transformers (CT) permanently installed on the feeders and equipment to be monitored.

How it works:

1. When an insulation fault occurs, it is detected by the IMD, which begins to inject an identifiable locating current signal into the power system
   
2. The locating current signal is detected by the measuring current transformers on faulted the circuit and is evaluated by the EDS fault location module
3. The fault location, determined by the EDS, is transmitted to the IMD module
4. Fault information is displayed locally on the IMD device, which can communicate the data via Modbus, e-mail, SMS or other communication method